US3393002A

US3393002A - Overshot retrieving tool

Info

Publication number: US3393002A
Application number: US441976A
Authority: US
Inventors: Brown J Woolley
Original assignee: Individual
Current assignee: Individual
Priority date: 1965-03-23
Filing date: 1965-03-23
Publication date: 1968-07-16
Anticipated expiration: 1985-07-16

Description

July 16, 1968 B; J. WooLLEY OVERSHOT RETRIEVING TOOL Filed March 23, 1965 July 16, 1968 B. J. wooLLEY ovERsHoT RETRIEVNG TooL Filed March 23, 1965 5 Sheets-Sheet 2 .5km/w rf Wool//ey July 16. 1968 B. J. WOOLLEY 3,393,002

OVERSHOT RETRIEVING TOOL Filed March 23, 1965 k5 Sheets-Sheet 3 .f5/own J. l/l/oo//ey INVENTOR.

, BY 224.10@ MM United States Patent O 3,393,002 OVERSHOT RETRIEVING TOOL Brown J. Woolley, P.O. Box 1249, Kilgore, Tex. 75662 Filed Mar. 23, 1965, Ser. No. 441,976 5 Claims. (Cl. 294-8623) ABSTRACT OF THE DISCLOSURE This invention relates to an overshot .retrieving tool that can be lowered into a well casing in an unlatched condition and released to grasp an object with a force that will increase as the Weight of the object is applied to the tool. The tool being so arranged that a downward as well as a rotational force can be applied to the object while i-t is being gripped.

This invention relates to new and useful improvements in overshot retrieving tools.

One object of the invention is to provide an improved retrieving tool, of the overshot type, which is capable of effectively engaging and gripping an object, such as a pipe or Stringer, which is stuck within a well casing or well bore, whereby said object, usually referred to as a fish, may be removed from said well casing or bore.

An important object of the invention is to provide an improved retrieving toOl which is lowerable into a Well bore upon a retrieving pipe and which has means for selectively applying an upward pull or jar on the stuck object, or applying a downward jar thereon, or if desired, applying a direct torque or turning force to said stuck object, whereby said object may be effectively released and subsequently removed from the well bore.

Another object of the invention is to provide an overshot retrieving -tool wherein the gripping means which is engageable with the stuck object or fish is so constructed that after it is firmly anchored in gripping position, a direct torque or turning force may be applied thereto and to said stuck object by means of ythe lowering or retrieving pipe; said torque assisting in releasing the object from its stuck position.

A further object is to provide a retrieving tool, of the character described, wherein the gripping means which engages the stuck object or fish is mounted so that the main portion or housing of the tool may be rotated relative to said gripping means after the gripping means has encompassed the fish but prior to movement of said gripping means into final gripping position; such arrangement assur-ing that rotation of Ithe tool housing and circulation of washing fluid can be continued to fully complete the washover operation before the gripping means moves into Ifinal gripping engagement with the fish.

Still another object is to provide a retrieving tool, of the character described, wherein the gripping means which is adapted to engage the stuck object is mounted within an -outer housing in such a manner that the gripping means may be selectively locked to the housing in a non-gripping position or may be unlocked for relative independent axial movement to permit setting of said means into gripping position with the stuck object; the selective loc-king or unlocking of the gripping means being controlled by the manipulation of the lowering pipe on which the outer housing of the tool is carried.

A particular object is to provide an overshot retrieving tool which permits proper washing over of the stuck object until said object is initially encompassed by the gripping means, at which time circulation of the washing fiuid is at least partially interrupted to provide a signal at the surface of the lwell bore indicating that said gripping means is in proper position to grip the stuck object or fish.

A specific object is to provide a tool, of the character described, which permits torque to be applied to the stuck object with neutral weight or with partial weight of the lowering pipe on the tool without disengaging the gripping means.

Another object is to provide an overshot retrieving tool having a connection assembly between the outer housing of the tool and the internal gripping means, which connection assembly is movable to two positions and functioning to lock the gripping means against setting when the -connection assembly is in one pOsition and to unlock said gripping means to allow setting when in a second position; the connection assembly being actuated by rotation of the outer housing through an improved friction clutch unit which is located between said housing and said connection assembly.

A further object is to provide an improved tool, of the character described, wherein the friction clutch unit tran-smits a rotation to the connection assembly upon initial right-hand rotation of the tool housing rela-tive -to said connection assembly; said clutch unit also providing a substantially positive drive to the connection assembly when the tool housing is rotated in a left-hand direction, whereby minimum left-hand rotation is required to Operate the connection assembly to thereby prevent unintentional breaking out of any thread connection in the retrieving pipe on which the tool is mounted.

The construction designed to carry out the invention will be hereinafter described, together with other features thereof.

The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings forming a part thereof, wherein an example of the invention is shown, and wherein:

FIGURE l is a' view, partly in elevation, and partly in section, illustrating the retrieving tool, constructed in accordance with the invention, and showing the same in position over the open end of the stuck object;

FIGURE 2 is a similar view illustrating the gripping means engaged with t-he stuck object;

FIGURE 3 is a view similar to FIGS. l and 2 showing the parts of the tool in the position after the gripping means has been released at which time the tool may be removed from the well bore;

FIGURE 4A is an isometric exploded view illustrating the upper four elements of the tool assembly;

FIGURE 4B is a similar isometric exploded view which is a continuation of FIG. 4A and showing the lower two elements of said tool;

FIGURE 5 is a horizontal cross-sectional view of the friction clutch unit illustrating the parts when the outer housing is rotated in a left-hand direcion when viewed from the top;

FIGURE 6 is a partial horizontal cross-sectional view of the friction clutch unit showing the position of the parts when the outer housing of the tool is rotated in a right-hand direction when viewed from the top; and

FIGURE 7 is a partial isometric view of one o f the friction clutch rings and one of the coacting slots in the member which coacts with a clutch ring.

In the drawings, the letter W designates a well bore within which an object O, such as a pipe, has become stuck by reason of cave-in of the formation or for some other reason. The retrieving tool constituting the present invention is generally indicated by the letter T and is adapted to be lowered into the well bore to encompass the stuck object. As will be explained the tool is provided with a gripping means which is adapted to connect the tool T to the stuck object, whereby an upward pull, a downward force or a torque or turning force may be applied to the stuck object to effect its release; thereafter the pull may be utilized to retrieve the freed object from the well bore.

As shown in FIGURE 1 the tool comprises a main outer housing 10 which has its upper end connected through a coupling 11 with a retrieving pipe, the lower end of which is indicated at 12. The extreme lower end of the tool T carries an annular cutter 13 whereby the tool may be lowered into the bore and may be rotated during such lowering, as it approaches the stuck object to cause the cutter to drill away any cave-in material which may be accumulated around the upper end of the stuck object O. At the same time that the cutting operation is being performed the usual uid may be circulated in either direction through the tool T and such circulation will of course wash the cuttings to the surface. The tool is best capable of carrying out a washover operation as it is lowered into position around the upper portion of the stuck object, sometimes referred to as the fish The main elements of the tool T include an annular bowl member generally indicated at A which element is connected through threads 14 with the lower end of the outer main housing 10. The cutter 13 is secured to the lower end of the bowl member. A gripping means generally indicated at B is disposed within the outer housing above the bowl member A and a latching or connection assembly generally indicated at C is positioned above and has connection with the gripping means B. The upper end of the latching assembly C has connection through a friction drive unit generally indicated at 4D with the outer housing. Said drive unit is retained by an inner retaining collar 15 which is threaded into the lower end of the coupling 11. The main elements A, B, C, and D, which are disposed within or connected to the outer housing T are illustrated in partial isometric views in FIGURES 4a and 4b.

Briefly, in the operation of tool T, the lower portion of the tool is moved into position over the upper portion of the stuck object or fish O, whereby said object moves upwardly within the bowl member A in the manner shown in FIGURE l. With the latching assembly C in a position which will permit relative movement of the gripping means B with respect to the outer housing 10 and the bowl member 14, an upward pull on the retrieving pipe and housing 10, as well as upon the bowl member A connected with the housing, results in moving the tapered surface 16 of the bowl into contact with the outer surfaces of the gripping means -B to thereby move the gripping means into tight engagement with the fish. At this time a continued upward pull on the retrieving pipe will result in an upward force being applied to the stuck object or fish; if the usual jars are connected in the retrieving pipe 12 an upward jarring force may be applied to the stuck object or fish O. Also, as will be explained in detail a right-hand rotation of the retrieving pipe will be transmitted through the outer housing 10 and bowl member A directly to the gripping means and therefore to the stuck object, whereby a torque or turning force may be applied. If desired, it is also possible to jar downwardly upon the gripping means B which is in engagement with the stuck object so that a downward force may be applied thereto. By reason of the selective application of forces, whether it be in an upward direction, a downward direction or a torque, the stuck object or fish O may be dislodged from its stuck position. After such dislodgement, the retrieving pipe may be utilized to lift the tool, together with the gripping means which is connected with the stuck object to thereby remove the same from the well bore. l

In the event that it isimpossible to dislodge lor free the stucle object, the latching assembly C may be actuated through manipulation of the pipe 12 and housing 10 to` latch the gripping means B in a position about the tapered bore 16 of the bowl member so that the entire tool may be released from the stuck object and may be removed from the well.

Referring to the specific construction of the tool the bowl member A is in the form of a tubular coupling having its upper end threaded to the lower end of the outer housing 10 and its lower end having internal threads for receiving the annular cutter 13. The upper portion of the bore is provided with the taper 16 which forms the bowl section (FIGURE 4b) and projecting inwardly from this tapered bowl are a plurality of elongate keys or lugs 17; the upper end of each key is inclined as shown at 1S. Since the bowl member A is directly connected to the housing 10 which, in turn is connected to the retriev-hA ing pipe 12 any movementof the retrieving pipe, either longitudinally or rotatively, of said pipe and housing will be imparted to the bowl member.

The gripping means B comprises a tubular body 19 having longitudinal slots 20 cut therein and extending upwardly from the lower end thereof. The lower portion of each slot is widened at 21 and this widened portion of the slot is adapted to receive the keys 17 within the bowl section 16 of the bowl member A. The external surface of the body 19 of the gripping means is inclined as indicated at 22 and this inclination is complementary to the inclination of the bowl section 16. When the gripping means body 19 is moved downwardly into the bowl 16 the coaction between the inclined surfaces moves the lower portions of the body 19 inwardly whereby teeth or gripping surfaces 23 provided on the inner surface of said lower portions may be urged into tight engagement with the stuck object. It is noted that the slots 21 not only provide for a direct connection between the gripping portions 22 of the means B and the bore member A by reason of the engagement of the portions 21 with the keys but also said slots, together with the narrow portion of the slots 20 impart a spring action to the lower portions 22 of said body. This spring action is such that when the fish or stuck object O first moves into the gripping means, the teeth 23 frictionally engage the external surface of said object. Of course, when relative movement between the bowl and the gripping means occurs in a direction to move the gripping teeth further inwardly, then a very tight engagement of the gripping means with the fish is obtained. A stop collar 24 has its upper portion threaded into the upper end of the body 19 of the gripping means, and as will be explained the lower end 25 of said collar limits the upward movement of the fish into the tool when the tool is initially moved into a position over said fish.

The position of the gripping means B within the housing 10 is controlled by the latching or connection assembly C. The latching assembly C is clearly shown in FIG- URE 4a and includes an inner sleeve 26 which has its lower end connected by threads 27 with the upper end of the body 19 of the gripping means. A plurality of splines 28 are formed on the exterior surface of the sleeve 26 and each spline has its upper end enlarged in a circumferential direction to form a shoulder 29. Since the sleeve 26 is secured to the gripping means body 19 it becomes a part of and is movable with said body.

An outer sleeve 30 completes the latching assembly C and this sleeve has a plurality of inwardly projecting splines 31 formed within its bore 32. The splines 31 of the outer sleeve 32 are adapted to be located between the splines 28 on the exterior of the inner sleeve 26 and in all positions of the tool, said splines are so located. However, the splines 31 may be moved beneath the shoulders 29 of the splines 28 in which event the upper ends 31a will engage beneath said shoulders 29. When in this position it will berpobvious that any upward movement of the outer sleeve 30 will result in the same upward movement of the sleeve 26 and therefore of the gripping means B. This may be referred to as the latched position and as will be explained when the inner and outer sleeves are latched together, the gripping means cannot move downwardly with respect to the outer sleeve 30; however, when the splines 31 are located between splines 28 then the gripping means B and its connected inner sleeve may undergo a limited axial movement with respect to the outer sleeve.

The upper portion of the outer sleeve 30 is enlarged at 33 and the friction clutch unit D, which will be hereinafter described, is mounted therein. The clutch unit coacts with the outer housing 1t) so that under certain conditions a friction drive is obtained between said main housing and the outer sleeve 30 of the latching assembly. With such arrangement, rotation of the main housing will impart rotation to the outer sleeve.

The outer sleeve 30 of the latching assembly C is confined against longitudinal movement with respect to the main housing 10 by means of a retaining collar 34 having an annular flange 35 on its lower end. This flange engages beneath the annular shoulder 35 formed between the bore 32 of the sleeve 30 and its enlarged upper end 33. The upper end of the collar 34 is threaded into the bottom of the coupling 11, being connected at the threads 37. As shown in FIGURES l to 3, the outer sleeve 30 of the latching -assembly is confined against longitudinal movement with respect to the main housing 10; however, because of the friction clutch unit D, the outer housing may at times impart a rotative movement to the sleeve 30, and at other times may rotate around said outer sleeve. In this way, the outer main housing may be utilized to control `and actuate the latching assembly C to locate the splines 31 of sleeve 30 with respect to the splines 28 of the inner sleeve 26 of said latching assembly.

The friction clutch unit D is illustrated in FIGURES 5 to 7 and comprises an upper friction ring 38 and a lower friction ring 39, which rings are mounted within an annular groove 40 formed in the exterior of the enlarged portion 33 of the outer sleeve 36 of the latching 1- assembly. As shown in FIGURE 5, the upper ring 38 is formed with an enlargement 41 having a tapered or inclined surface 42. The enlargement and its tapered surface is adapted to coact with a circumferentially extend* ing slot 43 cut into the wall of the enlarged upper end 33 of the outer sleeve 30 of the latching assembly. The slot 43 has a flat wall 44 defining one end thereof, while its opposite end is defined by -an inclined surface 45. The lower ring 39 is constructed in a manner similar to the upper ring and coacts with a slot 43a, shown in dotted lines in FIGURE 5, also in the wall of the enlarged portion 33 of the outer sleeve 30. It is noted that slot 43a is approximately 180 opposite the slot 43. However, both friction rings operate in the same manner.

It will be obvious by viewing FIGURE 5 that when the main housing 10 is rotated in a left-hand direction, the frictional engagement between the

rings

38 and 39 and the bore of the housing will cause said rings to rotate with the housing. Such rotation will cause the enlargement 41 and its inclined surface 42 to coact with the inclined surface 45 defining the end of the slot 43, and when this occurs, the friction ring is bound tightly between the housing and the upper end of the outer sleeve 30 of the latching assembly. This assures that a continued left-hand rotation of the housing will impart left-hand rotation to sleeve 30. By viewing FIGURE 4a, it will be seen that left-hand rotation of sleeve 30 with respect to the inner sleeve 26 of the latching assembly will move the internal splines 31 of said outer sleeve from beneath the lateral shoulder 29 of splines 28 of sleeve 26. It is, therefore, assured that the

sleeves

30 and 26 may undergo longitudinal movements with respect to each other.

Upon a rotation of the outer housing 10 in a righthand direction, which is indicated in FIGURE 6, the frictional engagement between the outer surface of ring 38 and the bore of the housing 10 will result in rotating the ring 38 with respect to the enlarged upper end 33 of the outer sleeve 30. The shoulder 41a formed -by the enlargement 41 will then engage the fiat surface 44 defining the opposite end of the slot, and this will halt further rotation of the ring 38 if the housing 30 and its enlarged upper end 33 are being held stationary. However, a continued right-hand rotation of the main housing 10 may occur, although there will be a frictional slipping motion between the outer housing and the r-ing 38.

The ring 39 coacts with its slot 43a in the same manner as the ring 38 and accomplishes the same function. Two rings are provided as a safety factor so that if one ring breaks or loses its resiliency, the other ring will still perform.

From the foregoing description of the friction drive clutch unit D, it will be evident that upon left-hand rotation of the outer housing, a positive drive between the outer housing and the outer sleeve 3i) of the latching assembly C is provided, so that positive rotation of sleeve 30 will move its splines 31 to what may be termed the unlatched position. Upon right-hand rotation, the friction drive between the outer housing and sleeve 30 assures that the splines 31 are moved beneath the shoulders 29 of splines 28 and this may be termed the latched position. If sleeve 26 is being held stationary by reason of the gripping means B engaging the pipe or stuck object, then after the splines 31 move beneath the shoulders 29 to their latched position, further rotation of the outer housing in a right-hand direction may occur without imparting that same rotation to the gripping means B. The -reason for setting up a more positive drive 'connection between the outer housing and the outer sleeve 30 of the latching assembly is to assure that the splines 31 of sleeve 30 are moved to the unlatched position without an excessive left-hand rotation of the outer housing. As is well known, the elimination of excessive left-hand rotation obviates the possibility of breaking out any of the threads in the retrieving string.

In the operation, the parts are assembled in the manner heretofore described with the gripping means B disposed within the interior of the main housing 10 and having the sleeve 26 of the latching assembly C connected to its upper end. The splines 28 of the sleeve 26 are interconnected with the splines 31 of the outer sleeve 30. During the running in operation, it is preferable that the splines be in unlatched position, that is, the splines 31 of outer sleeve 30 are disposed out of alignment with the shoulders 29 of the splines 28; however, it would make no difference to the operation if the

splines

31 and 28 are in engaged position in the manner shown in FIGURE 3.

The tool is lowered into the well bore and washing over of the upper portion of the stuck object or fish O is carried out by circulating fiuid downwardly through the tool and outwardly around the outside, or downwardly around the annular space and then upwardly through the tool. If a cavein formation is encountered before the stuck object enters the tool in the manner shown in FIG- URE l, the retrieving pipe may be rotated as lit is lowered so that the cutter 13 may perform the cutting -action while circulation is being carried out.

As the tool -moves into position over the stuck object or fish O in the manner shown in FIGURE l, the upper end of the fish will strike the lower end of the stop member 24. This member Imay be of different lengths so as to control the amount of the stuck object which will enter the tool. Upon the upper end of the object or fish striking the lower end 25 of the stop member 24, a restriction of the circulating fluid occurs, and such restri-ction of flow is indicated at the surface by a change in the pressure of the circulating fluid. In this manner, the operator yat the surface is advised that the tool is properly positioned in encompassing position over the upper portion of the stuck object. At this time the retrieving pipe 12 and the main housing 10 are rotated a slight distance in a left-hand direction, as viewed from the top; such left-hand rotation to the outer housing is transmitted through the

rings

38 and 39 of the friction drive unit D so that the outer sleeve 30 of the latching assembly C is rotated in a direction to move its splines 31 from beneath the shoulders 29. This slight left-hand rotation assures that the inner sleeve 2o' of the latch assembly and the gripping means B to which it is attached will thereafter be capable of a limited axial movement with respect to the outer housing and with respect to the bowl member A. It might be noted that as the stuck object or fish moved upwardly into the tool, it carried the slips upwardly to the position shown in FIG- URE l, and after the slight left-hand rotation has been imparted to assure the disconnection or unlatching of the

sleeves

30 and 26, the tool is ready to :be moved into its set position.

Setting of the tool is `accomplished by a straight upward pull on the retrieving pipe and upon the housing 10, which in turn transmits this same upward movement to the bowl member A. Such upward movement of the bowl member with respect to the gripping means forces the lower portions 22 of the gripping means B to more firmly engage the stuck object. It is noted that the lower portion of each section of the gripping elements is tapered toward a point 22a (FIGURE 4B), and these pointed surfaces, coasting with the inclined upper ends 18 of the keys 17 within the bowl section 16, assure that the keys 17 will be guided into the portions 21 of the slots in the gripping means B. This engagement of the keys with the slots of the gripping means sets up a direct rotative connection between the bowl member A and the gripping means B. This position of the parts is illustrated in FIGURE 2.

At this point the operator may rotate the retrieving pipe 12 and the outer housing 10` in a right-hand direction, and this rotation is transmitted directly through the bowl member A, keys 17 and slots 21 to the gripping means B, whereby a direct torque or turning force may be applied to the stuck object or fish O. If it is desired to 'apply an upward pull to the stuck object, it is only necessary to pull upwardly on the retrieving pipe and such pull is transmitted through the main housing 10 to the bowl member A and then to the gripping means which are in engagement with the stuck object. If jars are connected in the retrieving string, an upward jar may be effected. If it is desired to impart a downward ja-r, then the retrieving pipe is moved downwardly and the bowl member may be disengaged from the gripping members, but such members remain in engaged position with the pipe because of their inherent spring force. As soon as the housing 10 has moved downwardly a sufficient -distance to engage the lower end of the retaining collar 34 with the upper end of the inner sleeve 26 to which the gripping means is attached, a downward blow is imparted to the gripping means and to the stuck object. If the slips or gripping members of the means B become disengaged, a direct downward force can be transmitted through the inner sleeve 26 and through the stop member 24 directly to the upper end of the fish. It might be noted that the taper 16 in the bowl and the complementary taper on the gripping means members are at a relatively small angle with respect to the axis of the tool, this type of taper being known as a sticking or non-releasing taper. This means that even though an upward tension on the retrieving 'pipe was necessary to first set the slips, such tension may be relieved to a fairly substantial degree before the bowl member will disengage the gripping means. Thus it is possible to apply the torque or turning force even though tension on the pipe has been relieved.

As soon as the stuck object is dislodged or comes free, with the parts in the position shown in FIGURE 2, it is only necessary to lift upwardly on the housing and the stuck object may be retrieved.

In the event that the stuck object is not dislodged or freed and it is desired to remove the tool and Irelease its engagement from said fish, the retrieving pipe, housing and bowl member are moved downwardly to `release the engagement of the tapered surface 16 of the bowl from the gripping members of the I.gripping means. By the time the bowl member A has moved downwardly with respect to the slips, the upper ends of the splines 31 of the outer sleeve 30 of the latching assembly have moved into `a position below the lateral shoulders 29 on the inner sleeve 26 of said latching assembly. The outer housing is then rotated in a right-hand direction and through the friction drive rings 38 and 39 of the clutch drive unit D, a rotation is imparted to the outer sleeve 30 of the latching assembly which moves the splines 31 below the shoulders 29. This effectively limits the downward movement of the gripping means B with respect to the outer housing and maintains them in the position shown in FIGURE 3. In this position a retrieving pipe may be moved upwardly and the tool may be removed from the well bore W without any danger of the unintentional setting of the gripping means. The position of the parts during removal is illustrated in FIGURE 3.

From the foregoing it will be seen that a simple and rugged overshot retrieving tool is provided. The tool may be lowered into position an-d when the .gripping means thereof is set, it is possible to apply a torque or turning force to the stuck object. This is done `by rotating the outer housing in a right-hand direction, vand since there is a direct connection to the gripping means through the keys 17 of the bowl member, the torque or turning force may be applied even though tension has been relieved from the retrieving pipe. Also it is pos-sible to jar upwardly and to jar -downwardly on the fish to effect its dislodgement from its stuck position. If the stuck object is dislodged, then it is only necessary to retrieve the s-ame by an upward movement of the retrieving pipe and the tool.

In the event the tool can not remove the stuck object, it is possible, through the manipulation of the retrieving pipe and housing, to move the latch assembly into a latched position. In such position, the downward movement of the slips of the .gripping means B is limited to the point where said gripping means can not -be moved inwardly by the bowl section of the bowl member A. This assures that the tool may be released from the fish and removed from the well bore.

As illustrated in the drawings, the keys 17 provide a positive drive between the bowl member A and the gripping members of the gripping means. However, it is possible that the keys 17 could be eliminated and in place thereof, vertica-l teeth could be formed on the back side of the tapered portion 22 of the gripping elements of the gripping means. In this case, the external teeth would grip the tapered bowl section .16 sufficiently to permit a torque or turning movement to be applied'. Also in connection with the description, the clutch drive unit D has been described as being operated to be run on a pipe which would rotate in a right-hand direction to tighten its various couplings; obviously, -if left-hand pipe in which the couplings are tightened by left-hand rotation is employed, the clutch driving rings would be reversed. It is also pointed out that it is desirable that the gripping slips remain stationary while permiting a right-hand rotation of the outer housing. In the present instance, this is accomplished by rotating the clutch unit D between the outer sleeve 30 of the latching assembly and the housing. However, this type of friction clutch unit could be located between the body 19 of the gripping means and the lower end of the inner sleeve 26 of the latching assembly and accomplish the same purpose.

The foregoing disclosure and description of the invention is illustrative and explanatory thereof, and various changes in the size, shape and materials, as well as in the details of the illustrated construction, may be made Within the scope of the appended claims without departing from the spirit of the invention.

What I claim is:

1. A retrieving too-l adapted to be lowered on a retriew'ng pipe to retrieve a stuck object within a well bore including,

a main tubular housing, lowerable over and in encompassing relationship to a stuck object,

a bowl member having an internal tapered bowl section and connected to the lower portion of the housing,

gripping means within the housing and movable in a limited axial direction in the housing, whereby movement in one direction relative to the bowl section will move the gripping means inwardly to a gripping position with a stuck object, when the tool encompasses said object,

a latching assembly within the housing above said gripping means and having latching means for locking the gripping means against movement relative to the bowl section in the direction which would move the gripping means into gripping position,

actuation of the latching assembly unlocking the gripping means for movement relative to the bowl section to permit movement of the gripping means into a set position,

means directly connecting the latching assembly to the gripping means, and

means rotatively connecting the latching assembly to the main tubular housing, whereby selective rotation of said housing actuates said latching assembly,

said means rotatively connecting the latching assembly to the main tubular housing comprising, a friction drive unit having a friction drive ring which transmits right-hand rotation to the latching assembly and then permits slippage to occur whereby subsequent right-hand rotation of the housing may continue without further rotation of the assembly,

said friction drive ring setting up a substantially direct drive between said housing and said latching assembly when the housing is rotated in a left-hand direction.

2. A retrieving tool adapted to be lowered on a retrieving pipe to retrieve a stuck object within a well bore including,

a bowl member having an internal tapered bowl section and connected to the lower portion of the housgriping means within the housing and movable in a limited axial direction in the housing, whereby movement in one direction relative to the bowl section will move the gripping means inwardly to a Y gripping position with a stuck object, when the tool encompasses said object,

a latching assembly within the housing above said gripping means and having latching means forlocking the gripping means against movement relatlve to the bowl section in the direction which would move the gripping means into gripping position,

means directly connecting the latching assembly to the gripping means, and

said latching assembly comprises an inner sleeve which is directly connected to the gripping means and an outer sleeve having a rotatable connection with the main tubular housing whereby rotation of the housing transmits rotation to the outer sleeve,

said inner and outer sleeves ha-ving coacting splines which in one rotative position of the sleeves permits independent movement of the inner sleeve and gripping means relative to the outer housing and bowl member and in a different rotative position latches the inner sleeve to the.outer sleeve to prevent said independent move-ment of the inner sleeve and the gripping means with respect to the outer housing and bowl member,

said means which rotatively connects the latching assembly to the main housing comprising a friction drive unit including a friction drive ring between the assembly and the housing, and

means coacting with the drive ring and actuated upon rotation of the housing in a right-hand direction to rst impart rotation to the assembly and thereafter permits slippage to allow subsequent independent rotation of the housing with respect to the latching assembly,

said coacting means also setting up a substantially positive rotative connection between the housing and the latching assembly when the housing is rotated in a left-hand direction.

3. A retrieving tool adapted to be lowered on a retrieving pipe to retrieve a stuck object within a well bore including,

gripping means within the housing and movable in a limited axial direction in the housing, whereby movement in one direction relative to the bowl section will move the gnipping means inwardly to a gripping position with a stuck object, when the tool encompasses said object,

means directly connecting the latching assembly to the gripping means, and

clutch means rotatively connecting the latching assembly to the tubular housing whereby said housing may be rotated independently of said latching assembly and said gripping means and may actuate said latching assembly to release said gripping means,

said gripping means including a plurality of spaced apart gripping elements,

each of said gripping elements being tapered at its lower end, and

a plurality of keys in said bowl member and adapted to be positioned in the space between said gripping elements when said gripping elements are positioned in set position within said bowl whereby rotation of said housing is transmitted to said stuck object,

the upper end of each of said keys being inclined to coact with the tapered lower end of said gripping elements to assure that said gripping elements when unlocked may move downward into said bowl members between said keys.

4. A retrieving tool according to claim 3, including an annular cutter on the lower end of said bowl section whereby cutting over said stuck object may be performed as the tool is lowered into the well bore before said gripping elements are moved to set position.

5. A retrieving tool according to claim 3, including stop means adapted to engage the upper end of the stuck object for limiting the movement of said stuck object into the housing of the tool,

said stop means also functioning t0 impede Huid circulation through the tool when engaged by said stuck object to signal the position of said stuck object within said tool.

References Cited UNITED STATES PATENTS 705,931 7/1902 .Tass

Gates 294-8633 X Spang 294-8623 Edwards 294-8631 Corey 294-8623 Stohn 294-8631 X ROBERT G. SHERIDAN, Primary Examiner.

GERALD M. FORLENZA, Examiner.

lo G. F. ABRAHAM, Assistant Examiner.