US2737410A

US2737410A - Releasable rotary spear

Info

Publication number: US2737410A
Application number: US206623A
Authority: US
Inventors: Kendall R Stohn
Original assignee: Individual
Current assignee: Individual
Priority date: 1951-01-18
Filing date: 1951-01-18
Publication date: 1956-03-06
Anticipated expiration: 1973-03-06

Description

March 6, 1956 s o- 2,737,410 I RELEASABLE ROTARY SPEAR Filed Jan. 18, 1951 FIG.-5

FlG.-2

INVENTOR. Kendoll R. S'ohn r e@ a( m A TTORN EYS United States Patent O 2,737,410 RELEASABLE ROTARY SPEAR Kendall R. Stohn, Snyder, Tex.

Application January 18, 1951, Serial No. 206,623 6 Claims. (c. 294 99 This invention relates to oil well drillng tools and more particularly to an improvement in that class of tool commonly referred to as a spear. These spears are used on fishing strings to engage the fish internally and have also found wide use in connection with setting liners, holding and pullng casing, tubing and drill pipe and also for use with other tools. The spears are provided with so-called "slips to make the engagement when there is an Upward pull and are constructed to be readily releasable. In prior spears the'tool is conditioned for operation by a rotation of the drill string in one direction and made inoperative by a rotation in the opposite direction. Both right and left hand spears are employed. A right hand spear is one which is conditioned for operation by a right hand turning of the string and a left hand spear is one which is conditioned for operation by a left hand turning of the string. Under certain conditions a right hand spear is desirable and under other conditions a left hand spear is desirable. As spears are now constructed it is necessary to have two separate spears in order to have available both right and left hand spears, as no single spear is available which is capable of Operating as both a right and left hand spear.

One of the objects of my invention is to produce a single spear structure which can be quickly and easily adapted so as to be usable either for left or right hand operation.

Another object of the invention is to so construct a releasable rotary spear of the type employing wedges on a mandrel for actuating the slips carried by a surrounding cage that the spear can be changed from left to right hand operation or vice-versa merely by changing the normally inoperative relationship between the mandrel and cage.

Still a more specific object is to construct a releasable rotary spear of the type above referred to in which control slots and receivable lugs are so associated with the mandrel and cake that when the lugs are positioned in the slots in one relation left hand operation will be available, and when the lugs are positioned in the slots in another relation right hand operation will be available.

Still another object is to construct a releasable rotary spear which can be easily and quickly conditioned for either left or right hand operation, which will embody a minimum number of parts, be economical to manufacture, and be capable of the same high efiicient functioning, regardless of condition as to left or right hand operation.

Other objects of theinvention will become apparent from the following description taken in connectionwith the accompanying drawings in which:

Figure 1 is a side view, with parts in section, 'of a releasable rotary spear embodying my invention so as to be capable of either left or right hand operation;

Figure 2 is a cross, sectional view taken on the line 2-2 of Figure 1;

Figure 3 is a longitudinal sectional view taken on the ice line 3-3 of Figure 2, but showing the mandrel and cage in operative position;

Figure 4 is a perspective view of a part of the mandrel and cage section, showing details of Construction and relationship of the mandrel, cage and slips;

Figure 5 is a cross sectional view taken on the line 5-5 of Figure l, showing the control slots and lugs associated with the cage and mandrel with said lugs so positioned in the slots that' left hand turning of the drillng string must be made to condition the spear for operation; and

Figure 6 is a cross sectional View similar to Figure 6, but showing the cage and mandrel assembled in a manner that the lugs are so positioned in the slots that the right hand turning of the string must be made to condition the spear for operation.

Referring to the drawings in detail, my improved releasable rotary spear comprises essentially three members which are the mandrel M, the cage C and the slips S carried by the cage and arranged to cooperate with the mandrel. The mandrel M is an alongated member through which extends a passage 10 to permit fluid to be circulated through the spear. The upper end of the mandrel is provided with a threaded socket 11 whereby it can be connected to a threaded extension 12 on the lower end of a drill string D made up from a pluralty of hollow drill stem sections. The drill string, during drillng, has a bit attached to its bottom and the string extends down into the well bore and is rotatable and longitudinally movable by the drillng rig Situated on the surface at the top of the well bore.

Below the upper end of the mandrel is an enlarged shoulder portion 13 against which can abut the upper end of the cage C already referred to, said cage being in surrounding relation to the central section of the mandrel and capable of limited relative movement thereto, as will become apparent. Just below the shoulder 13 a reduced part 14 of the mandrel carries two diametrically positioned lugs or keys 15 which extend into slots 16 in the upper cylindrical end of the cage. The slots 16 are diametrically positioned and of a circum'ferential width considerably greater than the width of the lugs 15 so that the mandrel can have predetermined limited relative rotary movement with respect to the cage. The circumferential width of the slots with respect to the width of the lugs, in the particular spear shown, s such as to permit the mandrel to be rotated 60 degrees relative to the cage.

The lower end of the mandrel is provided with external threads 17 for attachment of a nut 18 having a conical end. l This nut carries a set screw 19 for lockng the nut in any-adjusted position on the'lower end of the mandrel, said set screw cooperating with a' smooth section of the end of the mandrel below the threads. The nut' limits the upward movement of the mandrel with respect to the cage. Thus it will be seen that with the nut 18 and the shoulder 13 at the top of the mandrel, the mandrel can move exially relative to the cage up and down in accordance with the difference in length between the length of the cage and the distance between the shoulder 13 and the nut.

The cage C, which is of general cylindrical shape, is provided with` three longitudinally extending windows 20, said windows being arranged degrees apart circumferentially around the cage. Positioned to cooperate with these windows and to extend therethrough are slips S, each of said

slips having flanges

22 and 23 on the ends for engaging with the cage wall at the ends of the windows and thereby limit the movement of each slip radially outwardly through the window. Each slip on `its outer surface is provided with gripping teeth 24 of saw-teeth sha-pe, whereby these grips, when pushed outwardly against the inner cylindrical surface of any member such as a tool, tube, casing or drill stern, can grip said surface and thereby connect the drill string carrying the spear with said internal surface. Each slip on its inner surface is provided with three inclined surfaces 25, said surfaces being in longitudinal alignment and having the same anglc of inclination with respect to the longitudinal axis of the slip.

Referring again to the mandrel M, the intermediate portion thereof which is surrounded by the cage is provided with a plurality of wedge portions 26 for cooperation with the inclined surfaces on the slips, there being a wedge for each inclined surface of a slip. With this arrangement it will be noted there are three rows of wedges with rows arranged 120 degrees apart about the axs of the mandrel. Each row has three wedges longitudinally aligned. The inclined surface of each wedge is the same as that of the inclined surface on the slip with which it is to cooperate so that there can be a wedging action over a considerable length whenever the mandrel is moved longitudinally relative to the slips and the wedges and the inclined surfaces on the slips are in cooperative relationship, as shown in Figure 3. To provide the proper surface engagement, the inclined surfaces on the slips and the surfaces on the Wedges will both be conical. The circumferential width of the inclined surfaces on the slips and the circumferential width of the wedges are such that the wedges can fit between the slips, this relationship being well shown in Figure 2 wherein it will be noted that the wedges are out of alignment with the slips and lie in between slips. When this arrangement is present between the mandrel and the slips, the spear is in inoperative condition and the. cage can have free longitudinal sliding movement with respect to the mandrel. Thus it will be possible to completely remove the cage from the mandrel whenever the nut is removed from the lower end of the mandrel. When th parts are assembled, however, it will be possible for the mandrel, whenever the cage and the mandrel are in the position shown in Pigure 3, to freely rotate the mandrel with respect to the cage and thus bring the wedges into cooperative relationship with the inclined surfaces on the slips so that there can be wedging action. When such wedging action is available, then any upward movement of the mandrel with respect to the cage will cause the slips to be forced radially outwardly so that the teeth on the outer surface of the slips can be forced into en agement with any cylindrical surface which it is desired to grip.

Whenever the wedges are in the position shown in Figure 2 which places the wedges out of alignment with the inclined surfaces of the slips, the lugs 15 carried by the mandrel will be at one side of the slots 16 in the cage. If it should be desired to use the spear as a socalled left hand spear, then when the cage and slips are assembled on the mandrel the lugs 15 will have the relationship with the slots 16 as shown in Figure 5 whenever the spear is inoperative, and by inoperative is meant when the wedges of the mandrel are out of alignment with the inclined surfaces on the slips, all as shown in Figure 2 and also as shown in dashed lines in Figura 5. To make the spear operative, under such conditions of assembly as viewed in Figures 2 and 5, it will be necessary to give the mandrel a left hand rotation which, as indicated by the arrow in Figure 5, will be a counterclockwise rotation. Such a rotation will move the lugs from the position shown in Figure 5 to a position at the opposite side of the slots 16 as shown in dotted lines in Figure S, provided, of course, that the cage is held from rotation during the rotation of the mandrel, which rotation is brought about by rotating the drill string. Such relative rotation of the mandrel will place the wedges in cooperative relationshp with the inclined surfaces on the slips and whenever the mandrel is pulled upwardly, the slips will be moved radially outwardly and a powerful gripping action will occur against the cylindrical surface engaged.

Whenever it should be desired to condition the spear and make it into a so-called right hand spear, the cage will be assembled onto the mandrel in a different relation with the mandrel than that just previously described. This assembly can be accomplished hy removing the nut, sliding the cage off the end of the mandrel and then putting it back on at a different angular relationship with the mandrei. This angular rclationship will be such that the lugs 15, when movedinto the slots 16, will have the position as shown in Figure 6 and the wcdges will be out of alignment with the inclined surfaces on the slips, as shown in dashed lines in said figure. With this condition of the lugs and slots, then the mandrei can have a limited (60 degrees) right hand or clockwise rotation with respect to the cage to bring the wedges on the mandrel into alignment with the inclined surfaces on the slips. When this cooperative relationship is established the slips can be forced radially outwardly by the wedging action between the wcdges and the inclined surfaces on the slips.

in order that the cage may be held from rotation with the mandrel whenever it is desired to rotate the mandrel from a position shown in Figure 2 to a position where the wedges on the mandrel are in alignment with the inclined surfaces on the slips, as shown in Figure 3, the outer surface of the cage is provided with three leaf springs 27 which will act as friction members. It will be noted from Figure 1 that the upper end of each leaf spring is attached to the upper end of the cage by screws 28 and the lower end of the springs are free. Thesprings lie on the outside of the cage between the windows through which the slips are movable. The surface of the cage has grooves 29 in which the spring can become positioned, thus it is possible to move the cage into a member having an internal diameter substantially the same as the external diameter of the cage since the spring, when flexed to a straight condition, will lie within the grooves 29. These springs, when engaging any internal cylind'ical surface in which the spear is positioned, will have sufiicient frictional engagement with such surface that the cage will be held from rotation so as to allow for the rotation of the mandrel relative to the cage in order to bring about the alignment and disalignment of the wedges and inclined surfaces on the slips.

From the above detailed description of rry improved rotary spear it is believed its operation will be apparent. However, a brief description of the operation will insure that the usefulness of the tool is clearly apparent, if it is not already so. Whenever it is desired to engage the spear with a tube, casing or other member having an inner surface, the spear, when attached to the lower end of the drill string, is lowered into the well bore and because of the tapered end of the nut 18 it will easily move into the opening of the member to be engaged. As the spear moves in, the leaf springs will engage the surface and cause the mandrel to move downwardly in the cage to the position shown in Figure 3. Under such conditions the upper end of the cage will engage the shoulder 13 of the mandrel and the mandrel will be in a position to be rotated relatively to the cage and thereby bring the wedge portions 26 into alignment with the inclined surfaces on the slips. The direction of rotation to accomplish this alignment will depend upon whether the cage has been assembled on the mandrel to cause the spear to be a left hand or a right hand spear. If the assernbly is as indicated in Figure 5 a left hand operation will be. available, and if the asesmbly is as shown in Figure 6 a right hand operation will be available. Since the cage is being frictionally held to the inner surface of the member to be engaged by the action of the leaf spring, relative rotary movement between the mandrel and the cage can be accomplished. The extent of relative rotation will be 60 ata-7,410

degrees for the particular spear disclosed. t After the inclined surfaces and wedges are aligned, the slps can be moved outwardly to grip the inner surface of the member to be engaged by pulling up on the drill string. This will force the teeth of the slps into tight engagement with the inner surface of the member to be engaged and the greater the pulling force, the greater the pressure that will be applied to the teeth.

To release the spear, the string and mandrel are moved downwardly with the result that the mandrel will again assume the position shown in Figure 3 where the slps will be permitted to move nwardly. If it is desired to place the spear in inoperative condition again, the mandrel will be given a reverse rotation from that given .to place the spear in operation. This reverse rotation will result in the wedges being moved out of algnment of the inclined surfaces of the slps and thus when the mandrel is pulled upwardly there will be relative longitudinal movement between the mandrel and the cage until the nut 18 engages the cage and causes it to move with the mandrel. The spear will then become completely disengaged from the member which it has gripped.

From the foregoing description it is believed to be apparent that my improved spear s very simple in construction and also easily operated. It is also believed to be apparent that the spear can either have left hand operation or right hand operation and the conditioning for either of said types of operation is accomplished in a very simple manner. All that needs to be done is remove the nut 18 from the lower end of the mandrel, slide the cage off the wedges and then give such a rotation that the lugs will have a different relationship with the slots. When the nut is replaced on the mandrel the spear is ready for use.

Being aware of the possibility of modifying the particular spear shown and described without departing from the fundamental principles of my invention, I desire it to be understood that the invention is not to be limited except in accordance with the appended claims.

What is claimed is:

l. In a well drilling tool for attachment to a drilling string for gripping the inner surface of a member and comprising a mandrel having three wedges thereon equally spaced circumferntially about its axis, a cage surrounding the mandrel and wedges, three slps mounted on the cage in equally spaced circumferential relation for radial movement and each provided with an inside inclined surface, means comprisng a cooperating lug and a circumferentially extending slot of greater length than the lug carried by the mandrel and cage being related so that the cage and mandrel can have relative rotary and relative longitudinal movement, said slot being of a circnmferential width in relation to the lug that the mandrel can rotate relatively to the slps in one direction only and thereby move the wedges from positions between slps to positions beneath inclined surfaces on the slips, other means including a second slot for receiving the lug so that the cage can be mounted on the mandrel in a manner that the mandrel can be moved in the opposite direction only and thereby move the wedges from positions between the slips to positions beneath inclined surfaces on the slps, a removable nut on the mandrel for limiting relative longitudinal movement between the mandrel and cage and when removed the cage will be allowed to be removed from the mandrel and then reassembled with the lug in a different slot, and means carried by the cage for frictionally holding the cage from turning when the tool is inserted in a bore of a member to be gripped.

2. In a releasable rotary spear, a mandrel, a cage constructed for mounting in surrounding relation on the mandrel in one position Ol' in a second position and for relative rotary and longitudinal movement between the mandrel and cage in each position, three circumferentially arranged slps having inclined surfaces and mounted in the cage 120 degrees apart for inward and outward movement relative to the cage, said mandrel being provided with three wedge means circurnferentially arranged degrees apart for cooperation with the inclined surfaces on the slps when in algnment therewith so as to move the slips outwardly by relative longitudinal movement between the mandrel and cage, said wedges and inclined surfaces having such circumferential widths that the mandrel, with the cage in either one of said positions, when rotated 60 degrees will place the wedges out of algnment with the inclined surfaces and in an inoperative condition and allow for relative movement of the wedges longitudinally past the inclined surface of the slps, and means carried by the cage and the mandrel and comprising two diametrically positioned lugs and two cooperating dametrically positioned slots for receiving the lugs, with the slots and lugs having such circumferential widths that the cage and mandrel can have a relative rotation of 60 degrees in either one of said positions whereby when the cage and mandrel are assembled in one position and the lugs are positioned in the slotsin one cooperating manner the mandrel can be rotated 60 degrees inone direction only to condition the wedges and slps for operation and when the assembly of the mandrel and cage is made in the second position with the lugs positioned in the slots in reverse the mandrel can be rotated 60 degrees in the opposite direction only to condition the wedges and slps for. operation.

3.' A well drilling tool for attachment to a drilling string and operable to grip the inner surface of a body, said tool comprising a mandrel having a plurality of circnmferentially spaced wedges thereon, a cage surrounding the mandrel and wedges and constructed for mounting on the mandrel in one position or in a second position and for relative rotary and longitudinal movement between the mandrel and cage in each position, members carried by the cage for outward radial movement relative to the cage and each provided with an inclined surface for cooperation with a wedge on the mandrel, and means comprising inter-engageable means carried by the mandrel and cage for limiting relative rotation between the cage and mandrel when the cage is mounted in either of said positions on the mandrel, each of said wedges and each of the inclined surfaces on the members having such a relation when the cage is mounted in either of said positions that upon relative rotation between the mandrel and cage in onevdirection, when the cage is in one position or in the opposite direction when the cage is in the second position, the wedges can be placed in cooperative relationshp with the inclined surface-s for wedging action or upon reverse relative rotation in either of the positions of the cage be placed in an inoperative relation in non-cooperation at opposite sides of the inclined surfaces, said mandrel being movable longitudinally during either of said cooperative relationships to cause radial movement of the members.

4. In a well drilling tool for attachment to a drilling string for gripping the inner surface of a member and comprising a mandrel having three wedges thereon equally spaced circumferentially about its axis, a cage surrounding the mandrel and wedges, three slps mounted on the cage in equally spaced circumferential relation for radial movement and each provided with an inside inclined surface, means comprising a cooperating lug and a circumferentially extending slot of greater length than the lug carried by the mandrel and cage being related so that the cage and mandrel can have relative rotary and relative longitudinal movement, said slot being of a circnmferential width in relation to the lug that the mandrel can rotate relatively to the slps in one direction only and thereby move the wedges from positions between slps to positions beneath inclined surfaces on the slps, and other meansincluding a second slot for receiving the lug so that the cage can be mounted on the mandrel in amanner that the mandrel can be moved in the opposite direction only and thereby` move the wedges from positions between the slips to positions beneath inclined surfaces on the slps.

5. A tool for gripping the inner surface of a member comprising a mandrel having a plurality of wedges thereon spaced circurnferentially about its axis, a cage surrounding the mandrel and wedges, -slips corresponding in number to the number of wedges mounted on the cage in spaced circumferential relation for radial movement and each provided with an inside inclined surface, means comprising a cooperating lug and a circumferentially extending slot of greater length than the lug carried by the mandrel and cage being related so that the cage and mandrel can have relative rotary and relative longitudinal movement, said slot being of a circumferential width in relation to. the lug that the mandrel can rotate relatively to the slips in one direction only and thereby move the wedges from positions between slips to positions 'beneath inclined surfaces on the slips, and other means including a second sIot for receiving the lug so that the cage can be mounted on the mandrel in a manner that the mandrel can be moved in the opposite direction only and thereby move the wedges from positions between the slips to positions beneath inclined surfaces on the slips.

6. In a well drilling tool for attachment to a drilling string for gripping the inner surface of a member and comprising a mandrel having three wedges thereon equally spaced circumferentially about its axs, a cage surrounding the mandrel and wedges, said cage being mountable on the mandrel in one position or in a second position,

three slips mounted on the cage in equally spaced circumferential relation for radial movement and each provided with an inside inclined surface, and means comprising two lugs carried by the mandrel and two circumferentially extending slots of greater length than the lugs carried by the cage for receiving the lugs and being related so that the mandrel can have rotary and longitudinal movement with respect to the cage, 'said slots being of a circumferential width in relation to the lugs that the mandrel can rotate relatively to the slips through an angle of sixty degrees, said slots being positioned so that when the lugs are therein in one relationship the cage is in one position with respect to the .mandrel and the mandrel can rotate in one direction only and thereby move the wedges from positions between slips to positions beneath inclned surfaces on the slips and when the lugs are reversed in the slots the cage is in the second position and the mandrel can be rotated in the opposite direction only and thereby move the wedges from positions between the slips to positions beneath inclincd surfaces on the slips.

References Cited in the file of this patent UNITED STATES PATENTS