US2903241A

US2903241A - Straight pull jar well tool

Info

Publication number: US2903241A
Application number: US515947A
Authority: US
Inventors: Ora A Brown
Original assignee: Joy Manufacturing Co
Current assignee: Joy Manufacturing Co
Priority date: 1955-06-16
Filing date: 1955-06-16
Publication date: 1959-09-08
Anticipated expiration: 1976-09-08

Description

P 1959 o. A. BROWN STRAIGHT PULL JAR WELL TOOL 3 Sheets-Sheet i Filed June 16, 1955 m \aaw J7 31 may. a e a a v? 1 I fl j 7 i I m 2 9 8 0 1 9 Z m R 3 Sept. 8, 1959 o. A. BROWN 2,903,241

' STRAIGHT PULL JAR WELL TOOL Filed June 16, 1955 3 Sheets-Sheet 2 A A Ll-r" A $1 4 7/ w .i WI IIIIIIIIIIIII IN V EN TOR.

I 0164 A. fleow/v 7- QE;Q 2? BY. l I 1 -22 4 I v Q f Arrmemsw Sept. 8, 1959 o. A. BROWN STRAIGHT PULL JAR WELL TOOL 3 Sheets-Sheet 3 Filed June 16, 1955 INVENTOR. 0/64 .14 Bea w/v I a? firraewzk STRAIGHT PULL JAR WELL TOOL Ora A. Brown, Whittier, Califi, assignor to Joy Manufacturing Company, Pittsburgh, Pa., a corporation of Pennsylvania Application June 16, 1955, Serial No. 515,947

Claims. (Cl. 255-27) This invention relates to a Well tool and more particularly to a well tool for imparting an upwardly directed force or jar to a fish lodged in a well hole, said tool being of the type commonly called straight pull jars.

In drilling operations in a well, a piece of drilling equipment which becomes lodged in a well hole, called a fish, may be dislodged by simply pulling upwardly on the drilling string. When this method is unsuccessful, it may be desirable to impart upwardly directed jars or jolts of selected magnitude to the fish to cause dislodgement thereof.

In prior proposed tools for imparting an upwardly directed force to a fish, control and regulation of the magnitude of the impact delivered to the fish was difiicult because of the particular construction of said prior tools. In such prior jar tools, themagnitude of the final impact delivered to the fish was dependent upon several variable factors, principally uncontrolled friction losses between parts of the tool. Tripping of jar tool at the proper time to deliver a preselected force to the fish was thereby subject to an uncontrollable friction factor in the well hole with the result that the jar to the fish may be too great or too little. Spring assemblies of disc or ring-type were used for determining release of trip meansto release the impact force and, in their spring design and arrangement, were not capable of transmitting full load through the spring assembly. As a result, the maximum effective use of the jar tool was not possible.

This invention contemplates a well tool for delivering an upwardly directed, positively controlled impact force of preselected magnitude to a fish and operable by applying a straight, upwardly directed pull in the drilling string.

The well tool of this invention is so constructed and arranged that the magnitude of the impact force may be readily and accurately determined. The invention contemplates novel means for release of the impact force whereby friction factors between parts of the tool have little or no effect on the magnitude of the force delivered.

The present invention contemplates means for readily, accurately, finely adjusting the compression or amount of deflexion of a spring assembly so as to accurately determine the magnitude of force released by the tool.

It is, therefore, the primary object of this invention to disclose and provide a novel well tool for imparting an upwardly directed force of selected magnitude to a fish.

An object of this invention is to disclose and provide a novel arrangement of trip finger means for releasing the tool from set position to impart a preselected force to a fish.

Another object of this invention is to disclose and provide a well tool of the straight pull jar type wherein a spring assembly may be loaded to full compressive Un ted ew Pat ,0."

strength and into a solid condition of maximum deflexion I of selected magnitude to a fish.

2,903,241 Patented Sept. 8, 19 59 'ice The invention contemplates a spring assembly wherein load bearing faces are selectively contoured so as to cause a force transmitted through the springs to move into. a selected full load transmitting location.

- Generally speaking, the invention contemplates a we tool of straight pull jar type which includes an elongated, hollow body means provided with an internal, upwardly directed hammer face. Within the body member a mandrel means is provided with a downwardly directed anvil face to be struck by the hammer face, said mandrel means extending below the body member for connection in suitable, well known manner to a fish to be dislodged. Between the mandrel means and the body means is a compressible spring assembly, said spring assembly being seated at one end on an adjustable mandrel nut and at its other end on a plurality of trip fingers, said trip fingers having finger end portions expandably movable outwardly by a biased latch sleeve slidably carried on the mandrel means. The finger end portions and the body means are provided with complementary releasable engagement means interlocked when in tool set position and held or trapped in interlocked relation by said latch sleeve. The engagement means are releasable when an upward strain placed on the body member compresses the spring assembly to a preselected load. Release of the fingers at the selected load permits the body means to continue to move upwardly to cause the hammer face to forcibly strike the anvil face on the mandrel means. The trapped engagement means permits release of the fingers only when the spring assembly is deflected to its preselected compressive load which controls the magnitude of the jar delivered to the mandrel means. H

Other objects and advantages of this invention will be readily apparent from the following description of the drawings.

In the drawings:

Figs. 1, 1a and 1b are a longitudinal sectional view of a well tool embodying this invention, the section being taken in a plane passing through the axis of the tool, Fig. 1a being a continuation of Fig. 1 and Fig. lb being a continuation of Fig. 1a. Figs. 1, la and 1b show the well tool in set position.

Fig. 2 is a fragmentary sectional view taken in the same plane as Fig. 1 showing theparts of the tool in Fig. 1a in released or tripped position, the remainder of the tool parts being extended but not involving a different coaction.

Fig. 3 is a transverse sectional view taken in the plane indicated by line IIIIII of Fig. 1b.

Fig. 4 is a plan of the spline maze of Fig. lb in which the normally cylindrically arranged splines have been unfolded into a plane.

Fig. 5 is a view similar to Fig. 4 showing relative positions of the splines in the spline maze upon selected rotation and relative longitudinal movement of parts of the tool means.

Fig. 6 is an enlarged perspective view of the trip finger assembly employed in this invention and shown in Figs. 1a and 2.

Fig. 7 is an enlarged perspective view, partly in sec tion, of adjustment means shown in Fig. l.

Fig. 8 is a transverse sectional View taken in the plane indicated by line VIIIVIII of Fig. l.

Fig. 9 is an enlarged sectional view of the adjustment means shown in Fig. 1.

The well tool means of this invention is generally indicated at 15. At the top of tool 15, a hollow body means 16 may be threadedly connected to a drilling string 17. At the bottom of tool 15 may project a lower portion of an internal mandrel means generally indicated at 18, said mandrel means being connected as at 19 to a suitable sub '20 having a connection to a fish (not shown) to be jarred by tool 15.

The well tool means 15 comprises the elongated, hollow body or barrel means 16 including aniupper' hollow body member 22 having a threaded connection at its top at '23 to a top body sub 24 which is connected to the drilling string. The bottom of the upper body member '22 is threadedly connected at 25 to the top 'of a lower hollow body member 26. The bottom of the lower body "member 26-is'threadedly connected at 27 to'a body knocker sub 28. The knocker sub 28 is provided with a top annular hammer face 29 pos'itioned'within the lower body member 26.

The bottom portion of the knocker sub 28 may be provided with an enlarged, elongated, hollow opening 30 and with longitudinallyspaced alternately arranged'up-per and lower extending internal splines 31. Thesplines 31 alternately inter-leave upon relative longitudinal and rotative movement with longitudinally overlapped alternately arranged upper and lower external splines 32 provided on a lower mandrel member 34. Upper and

lower splines

31 and 32 form a spline maze arranged and spaced to facilitate incremental relative rotation of the body means 16 and the mandrel means 18 to adjust the striking force of the tool as later described.

The mandrel means 18 isprovided with a through bore 35 throughout its length and includes a top wash pipe 36 positioned within the top sub 24. The wash pipe 36 may be provided with an enlarged hollow bottom portion 37 having internal threads forthreaded engagement as'at 38 with-an upper mandrel member 39. The upper mandrel member 39 extends in coaxial spaced relation within body member 26, said anvil face 43 being opposed to and spaced from the hammer edge face'29 a distance indicated by X when tool 15 is in setpositio'n. v

The magnitude of an impact force delivered by ham- "mer-face 29to anvil face 43 is dependent upon predetermined compression stressing or deflection of a spring assembly 45. The spring assembly 45 is positionedin an annular space between upper body member 22 and upper 'mandrel member 39 and may comprise a plurality of coaxially arranged disc or ring-type springs 120 sleeved "over upper mandrel member 39. The top of spring assembly 45 may be seated against an annular edge face 47 provided on an adjustment nut 48'thre'ade'dly connect "ed at 49 to an elongated threaded portion '50 of the upper mandrel member 39 for selected longitudinal adjustment of the not.

The lower end of spring assembly 45 may be seated on an upper annular surface 52 of a spring seating ring 53. The lower annular edge face of the seating ring 53 provides a seat as at 54 for tool setting and releasing --trip means including a plurality of elongated trip or stress transmitting fingers 56 arranged in assembly about the mandrel member 39.

Fingers 56 include enlargedoutwardly directed heads 57 provided with outwardly facing aligned grooves 58 to receive a circular retaining element 59 for holding the heads 57 of fingers 56 in assembly around the mandrel member 39. End face 55 on each finger head may be convexly curved to provide rocking engagement with the lower edge face of seatingring 53. Each finger 56 ineludes an elongated shank 60 having less thicknessxthan head S7, terminating in a bottom inwardly and upwardly inclined latch engaging edgeface 61. Each shank'60'is '66 and the trip collar 81 .provided, adjacent to its lower end, with a plurality of longitudinally spaced transversely arranged outwardly directed ribs 62 defining therebetween recesses 63 and forming engagement means. Top recess 63 may be of somewhat greater length than the other recesses 63 and the ribs and recesses may be contoured as shown. The internal end face of shank 60 may be provided with an internal recess 65 defining a shoulder 64. It will thus be noted that while the heads 57 of the fingers 56 are held in assembly about the mandrel member 39, the lower ends of fingers 56 are free to'laterally expand and move outwardly toward the upper body member 22.

The trip means may also include a latch sleevemember 66 slidably carried by the upper mandrel member 39 below the trip fingers. The latch member 66 includes a top downwardly and outwardly inclined annular finger engaging edge face 67 for cooperable engagement with the inclined-edge face 61 on each finger 56. The latch 'member 66 may be provided with latch portion 6611 defined by external shoulder 68 spaced from edge face 67 and similarly inclined. Latch portion 6611 having a circumaxial'surface is receivable within recess 65, recess 65 being bored to a diameter to readily receive the latchportion 66a when fingers 56 are in lateral expanded position (as in tool set condition).

The lower portion of latch member 66 may be .pro vided with an inturned lip 69 for engagement with a collar 70 on the mandrel member 39. The collar 70 is received within an enlarged internal annular recess 71 provided in thelowerportion of the sleeve member 66, said collar 70 limiting longitudinal movement of lateh member 66 on the mandrel member 39. To facilitate as sembly, latch member 66 may be formed as a splitsleeve, said latch member being retained by an external retaining member 73 having an upwardly directed skirt 74 on compassing the lower portion of the latch member 66 and having an inturned bottom rib 76 for seating of the lower edge faceofthe latch member. The latch member66 may be biased upwardly by a coil spring77 seated at its top end at 78 against rib 76 and seated at its bottom end at 79'against anupwardly facing shoulder defined by enlarged portion 40 of mandrel member 39.

The trip'mea'ns may also include an internal trip collar 81 fitted within the lower portion of the upper bodymember 22 and secured against longitudinal movementby' a channel shaped split ring 82'Which interlocks the top end of the lower body member26 and the lower end of the collar 81 just above threaded connection 25. The trip collar 81 includes engagement means comprising a plurality of longitudinally spaced annular internal ribs 83 defining'intern'al' recesses 84 therebetween having a profile means on'e'achfi'ngers 56 isr'ele'asably interengaged-(Fig. 1a) with the engagement means on the trip collar 81 and the lowermost portion'of each finger 56 is trapped between the upper latch portion 66a of the latch member In tripped or releasedposition (Fig. 2') the lower :end portions-of the fingers '56 are disengaged from trip collar 81 which'is now positioned'adjacenttoheads 57 of said fingers, and the fingers lie in substantially parallel relation tothe upper mandrel member 39.

spring assembly 45. *Asslio'wn in'Fig. 9,-in a chamber at the opposite end of nut'4'8 may be provided brake -me'ans "88 for preventing unwanted relative rotation 'of the nuton' the mandrel member. Thebrake means 88 may comprise annular brake"discs"89'and'90interleaved for frictional engagement therebetween provided with friction wear pads 138. Brake disc 89 is provided with an external key 91 cooperable with a longitudinal slot 92 on the nut. The brake disc 90 includes an internal key 93 cooperably received within an elongated, longitudinal slot 94 in the mandrel member 39. A plurality of springs 95 carried by the nut 48 biases the

brake discs

89 and 90 into frictional engagement and said brake means may be suitably retained by a snap ring 96 carried by nut 48.

A castellated nut sleeve means 97 is threaded on the top portion of nut 48, said nut sleeve being provided with castellated end portions or

teeth

98 and 99. The castellated end portion 98 adjustably cooperates with a key 100 retained in nut 4-3 by a ring 101 to prevent relative rotation of nut sleeve 97 with the nut 48 after the nut sleeve has been selectively adjusted on the nut 48 when the tool is initially assembled and set for a particular spring assembly.

The castellated end portion 99 is provided with inclined end faces 99* and extends upwardly to interengage with ratchet teeth 102 on the lower end of a ratchet sleeve 103 carried by the mandrel member 39. The ratchet teeth 102 are provided with inclined end faces 102a. The ratchet sleeve 103 is biased downwardly toward nut 48 by a spring 104 carried by sleeve 103 and seated at its top end against the bottom edge face of pipe 36. Sleeve 103 is positioned by contact with an annular stop shoulder 105 on the mandrel member 39. At its upper end the ratchet sleeve is provided with a plurality of longitudinally extending external splines 106 cooperable with internal splines 107 provided on the top body sub 24.

Adjustment of compression of spring assembly 45 is accomplished by lowering the body means 16 including top body sub 24 relative to the mandrel means 18 to interengage splines 107 on sub 24 with splines 106 on ratchet sleeve 103 to rotate nut 48 through interengagement of ratchet teeth 102 with teeth 99 on nut sleeve 97. The amount of relative rotation between body means 16 and mandrel means 18 is limited by the spline maze on the body knocker sub 28 and on the lower mandrel member 34 at the lower end of the tool. As shown in Fig. 5, incremental rotation of the body means (to the right) relative to the mandrel means has been completed and side faces of body splines 31 contact opposed side faces of splines 32. For further relative righthand rotation, the body means 16 is raised lifting body splines 31 above their associated mandrel splines and at the same

time disengaging splines

106 and 107 at the top of the tool. The body means 16 is then further rotated to pass above the previously contacted spline 32 and then lowered to interengage

splines

106 and 107. In this second lowered position, incremental rotation of the body means relative to the mandrel means is limitedly permitted until the side faces of

splines

31 and 32 are again in contact. While raising body means 16, engagement of teeth 102 on the ratchet sleeve 103 with teeth 99 on the nut sleeve 97 is undisturbed, and when the body means is lowered again, interengagement of

splines

106 and 107 and then further incremental rotation of the body means will cause the nut 48 to incrementally rotate on the threaded portion 50 through torque transmitted by

splines

106 and 107. Therefore, by alternately raising and lowering the body means 16 with respect to the mandrel means 18 and applying torque to the body means, the adjustment nut 48 can be incrementally tightened downwardly on the threaded portion 50 to finely adjust the spring assembly to a preselected compression as by counting the number of times the body means is raised and lowered.

In maximum downward position of nut 48, the teeth 99 on the nut sleeves 97 are virtually withdrawn from between teeth 102 on ratchet sleeve 103 since ratchet sleeve 103 is stopped from downward movement beyond stop shoulder 105 on the mandrel member 39. Maximum downward position is thus determined when the inclined bottom faces 102a begin to slip over the correspondingly inclinedtop faces 99a of teeth 99; Thus, further compression of spring assembly 45 is prevented by slipping of these

inclined faces

102a and 99a in the direction of rotation for tightening nut 48. Thus, the spring assembly cannot be overloaded or overset upon further rotation of the body member. From this maximum load position, the nut 40 may be adjusted upwardly to decrease the amount of compression in the spring assembly by reversing relative rotation (to the left) of the body member and the mandrel member, the body member being moved upwardly and downwardly with respect to the mandrel member to work through the spline maze and to incrementally loosen the nut. Reverse rotation of the body means 16 is effective to loosen nut 48 because when the

splines

106 and 107 are engaged, lefthand rotation of ratchet sleeve 103 causes abutment of the lowermost edge portions of teeth 102 with the uppermost edge portions of teeth 99 so as to cause incremental unloosening rotation of nut 48.

The wash pipe 36 is carried. in the top body sub 24 for relative sliding movement therewith. A suitable packing gland 116 may be seated against an upwardly directed internal shoulder 117 formed within the top sub 24. Above packing gland 116 may be provided a top gland positioning and compression sleeve 10% encircling the top of the wash pipe 36, said sleeve 10% being seated at its top end against an internal adjustment nut 109 threaded as at 110 in the top sub 24. The internal nut 109 may be provided with a castellated top edge 111 for cooperation with a retaining spring ring element 112 having a bent end 113 adapted to extend downwardly into the openings formed in the castellated top edge 111. Release of end 113 may be provided by removing a set screw 114 threaded in the top sub 24 and pressing the end 113 inwardly by an elongated narrow tool similar to a nail or the like.

' It is understood that before running the well tool into a Well hole nut sleeve 97 has been properly adjusted to limit travel of nut 40 so that, at full load maximum deflection of spring assembly 45, the ratchet sleeve and cooperable teeth on the nut sleeve will be operable to prevent overloading of the spring assembly as described above. It is also understood that nut 48 has been adjustably positioned on the threaded portion 50 of the mandrel member so as to allow selected compression of spring assembly 15 to release fingers 56 at a selected strain on the drilling string to deliver to the mandrel means a selected magnitude of jarring force.

Before setting of the tool it will be apparent that the fingers 56 are under compression between the latch member and the spring assembly 45 as a result of biasing spring 77. The fingers are restrained from lateral expansion by the encircling trip collar 01.

To set the tool the drilling string and body means are lowered to space apart the hammer face 29 and anvil face 43. As the body member moves downwardly the trip collar 31 moves downwardly along the fingers 56 until the engagement means 62, 63 on the trip collar are opposite the engagement means 83, 84 on the fingers. At this point the fingers (under compression) snap outwardly to interlock the said engagement means. This outward movement is facilitated by the inclined faces 61 on the fingers and the inclined cooperable face 67 on the latch member. Immediately after the latch fingers 56 interengage with the trip collar 01, the latch member 66 is urged upwardly by spring 77 between the mandrel member 39 and the lower finger end portions, thus trapping said finger end portions between the upper portion 66a of the latch member and trip collar 81. In this set position the fingers 56 cannot disengage the trip collar until the body member has been raised sufficiently to .compress the spring assembly a preselected amount.

is transmitted through the engagement means of the trip {collar to fingers 56 and then to the spring assembly 45. 'The upward strain is continued until the spring assembly 45 is compressed to a preselected amount as measured by deflection of the spring assembly. As this point is reached the inner edges of inclined faces 61 on the fingers are opposite the external edge on inclined face 67 on the latch member. At this point the inclined faces wedgingly 'coact to force the latch member downwardly against its spring 77. Since the compression force stored in the spring assembly is many times greater than the upward biasing force of the Spring 77, the latch member snaps downwardly, the fingers 56 virtually, instantaneously disengage from the trip collar, and the body means snaps upwardly to relieve the strain placed thereon and the hammer face 29 forcibly strikes the anvil face 43 on the mandrel means. The impact force delivered to the anvil face 43 is thus virtually equivalent to the force required to compress the spring assembly 45 to the point where the 'latch fingers are released. Thus the force delivered is virtually unaffected by friction factors present in the tool means.

Successive blows may be applied to the anvil face 43 on the mandrel means by lowering the body member, setting the tool, and then taking an upward strain'on the drilling string. The successive impacts thus delivered are of virtually the same magnitude because the compression of the spring means 45 in each instance is substantially the same. In the event it is desired to increase or de crease the magnitude of the impact force adjustment of the amount of deflection required by the spring assembly 45 to release the fingers 56 from set position may be readily made as above described by rotation of the adjustment nut 48 on the mandrel member.

It will thus be apparent that in operation of the well tool of this invention upward strain may be taken on the drilling string and may be transmitted directly through the spring assembly without overstressing the spring ass'embly because it is able to transmit the full load in a solid condition. Such upward strain may be taken when the tool is in tripped position and the strain forces are transmitted through the hammer and anvil edge faces 29 and 43. When the tool is in set position as shown in Figs. 1, 1a and lb, upward strain is transmitted from the body means to the finger assembly 56 and then through the spring assembly 45. In set position the lower ends of fingers 56 are trapped between the collar 81 and the latch portion 66a so that the fingers 56 cannot be released until a preselected stress is applied to the body means. The release moment is dependent upon ftheamount of deflexion in the spring assembly 45 and at selected defiexi'on the trip fingers 56 snap inwardly and the latch member 66 snaps downwardly in order to per- 'mit the body means to move upwardly to deliver the impact blow against the anvil edge face 43 on the mandrel means. Since the fingers 56 are trapped until the selected release position, a preselected magnitude of impact force is assured for delivery against the mandrel means.

Because the amount of deflexion of the spring body 45 is relatively small as related to the pounds of striking force to the delivery, the adjustment means for controlling the amount of deflexion of the spring assembly provides a convenient, readily controllable arrangement for accurately and finely adjusting incrementally the magnitude of the force required to trip the Well tool.

It will, thus, be readily apparent to those skilled in the art that the operation of the well tool means of this invention virtually eliminates the influence of friction forces -as related to the parts of the well tool which are conear tool means of this invention and in its operation thereof which come within the spirit of the invention. All

8 such modifications and changes coming within the scope of the appended claims are embraced thereby.

I claim:

1. In a well tool, the combination of: a hollow body means provided with an internal, upwardly directed hammer face; a mandrel means within the body means pro vided with a downwardly directed anvil face opposing said hammer face; a spring assembly positioned between said body means and said mandrel means; a biased latch sleeve slidable on the mandrel means and spaced from the spring assembly; a plurality of trip fingers extending between and cooperable with the spring assembly and the latch sleeve and having finger end portions adapted to be expanded outwardly by said latch sleeve; and an internal trip collar member carried by the body means, encircling the fingers, and movable longitudinally of the fingers, said finger end portions and said trip collar member having complementary engagement means cooperable in tool set position, said latch sleeve being movable between the tary inclined annular face for engagement therewith.

3. A well tool means as stated in claim 1 wherein said latch sleeve includes an external cylindrical face for sliding engagement with an internal face on said fingers.

4. A well tool means as stated in claim 1 including spring means on said mandrel means for biasing said latch sleeve.

5. A well tool means as stated in claim 1 wherein means on the mandrel means and means on the body means cooperably engage to adjust compression of the spring assembly.

6. A trip assembly for a well tool including coaxially, telescopically arranged, relatively movable, hollow members comprising, in combination: a plurality of trip fingers slidably biased on one member and having end portions provided with engagement means; means on said one member normally stressing said trip fingers to urge said end portions of said fingers outwardly into expanded position; a trip collar on the other member encircling the fingers, movable longitudinally thereof, and provided with engagement means complementary to the engagement means on said fingers; said stressing means including a biased latch member movable upon expansion of said fingers between said finger end portions and the said one member whereby said finger end portions are trapped between said latch member and said trip collar.

7. A trip assembly for a well tool including telescopically arranged, relatively movable, hollow members comprising, in combination: trip finger means slidably biased on one of said members and having finger portions provided with engagement means; means on one member placing said finger means under compression to urge said finger portions toward the other member; a trip collar carried by said other member positioned adjacent said trip means and provided with engagement means complementary to the engagement means on said finger portions; said means for placing said finger means under compression including a biased latch member positioned between said relatively movable members to urge said finger portions toward said trip collar to interengage said engagement means on said collar and on said finger means and for interlocking said engagement means in tool set position.

8. In combination with a well tool having relatively movable, coaxially arranged, spaced inner and outer members and a spring means positioned between said members: means to adjustably incrementally compress said spring means comprising an adjustable nut threaded on the inner member and adapted to bear against one end of'the spring means; castellated means carried by the nut; a sleeve member on the inner member provided with ratchet teeth to interengage the castellated means and provided with external, longitudinally extending splines; and internal splines on the outer member to engage the external splines on the inner member upon relative Iongitudinal movement therebetween and to transmit torque from the outer member to said adjustable nut upon relative rotative movement between said inner and outer members.

9. In a well tool as stated in claim 8 wherein said castellated means are adjustably threaded and fixed on said nut to limit depth of engagement between said castellated means and ratchet teeth on said sleeve member whereby overstressing of said spring assembly is prevented.

10. In combination with a well tool as stated in claim 8: spline maze means including longitudinally spaced internal splines on said outer member and longitudinally overlapped external splines on said inner member; said splines in one position of relative longitudinal movement tive rotation of said inner and outer members with interengagement of said castellated means on said nut and ratchet teeth on said sleeve member.

References Cited in the file of this patent UNITED STATES PATENTS 2,008,743 Black July 23, 1935 2,008,765 McCullough July 23, 1935 2,016,607 McCullough Oct. 8, 1935 2,144,869 Boulter Ian. 24, 1939 2,166,299 Kennedy et al July 18, 1939 2,336,564 Osmun Dec. 14, 1943 2,618,466 Bagnell et a1. -t... Nov. 18, 1952 2,675,225 Migny Apr. 13, 1954 2,708,110 Clay May 10, 1955