US2072338A

US2072338A - Oil well grapple

Info

Publication number: US2072338A
Application number: US66667A
Authority: US
Inventors: Clarence A Kelso
Original assignee: Individual
Current assignee: Individual
Priority date: 1936-03-02
Filing date: 1936-03-02
Publication date: 1937-03-02
Anticipated expiration: 1954-03-02

Description

March 2 1937. c. A. KELSO OIL WELL GRAPPLES Filed March 2, 1936 4 Sheets-Sheet l .FIqQ/ March 2, 1937. c. A. KELSO OIL WELL GRAPPLES Filed March 2. 1936 4 Sheets-Sheet 2 N VENTOR.

March 2, 1937. c. A. KELSO on. WELL GRAPPLES Filed Marh 2. 1936 4 Sheefis-Sheet 3 /NVENTOR Marbh 2, 1937. A KEL v 2,072,338

on. WELL GRAPPLES Filed March 2. 1936 4'Sheets-Sheet 4 I Patented Mar... *2, 1937 UNITED STATES 11 Claim;

PREMISED CONDITIONS or OPERATION The type of grapple shown in the drawings and hereinafter described is intended to be used in conjunction with the regular equipment conof about two miles. In drilling these deep wells the drill may be deflected, intentionally or otherwise, so that the lower portion of the hole is considerably off the vertical, and, in some cases, 5 nearly horizontal.

As is the usual practice during the actual drilling operations, the well is full of fluid, or drilling mud, so called. It is assumed that the upper portion of the pipe to be recovered is leaning against the side of therhole rather than being axially disposed in the well. Depending upon the depth down to the break, the weight of the pipe to be recovered may be anywhere from a few hundred pounds to one hundred tons, and the break might be either just above or just below a hub on the pipe.

The foregoingstatement of premised operat-' ing conditions is merely indicative of the complex nature of a so-called fishing job to re- 40 cover a lost tool from an oil weel. An object of this invention is to provide a grapple for the one of the deep wells, the amount of labor involved and the time required to assemble a grapple and drill pipe and to lower the same in the hole to the proximity of the break are consider- I able. Where a heavy drilling fluid is used in the well it is highly important that the lost tool be (Ell. 294-86) recovered quickly. It may require more than one I try to effect a satisfactory hold of grapple on the lost pipes In line with this, it is an object of this invention to provide means in the grapple whereby repeatedly to open and close the grapple in place at the site of the break, thus to avoid the necessity of withdrawing the tool from the hole to open the device if it should be accidentally closed, or if the first attempt or attempts to effect a firm hold'on the lost pipe should be unsuccessful.

Other objects of that invention appear as the invention is more fully disclosed.

I attain the objects of my invention by means of the instrumentalities set forth in the appended claims, of which the drawings are merely illustrative, it being understood that variations in the mechanism can be made to conform with other conditions of operation and in arts other than oil wells, without departing from the invention.

In the drawings and specification, similar parts are referred to by'like characters of reference throughout.

. BRIEF DESCRIPTION Figure 1 is a combined vertical section and elevation of the grapple with a section of drill pipe inclasped therein. In this view the grapple is supposed to be suspended in a well, and the phase indicated is that which occurs during the inclasping operation but before any upward pull is exerted on the lost pipe string. This view of the grapple is broken to accommodate it to the size of the drawing, and exterior and intermediate parts are broken away to show interior construction. 1

Figure 2 is a cross section through Fig. 1 at the plane indicated by 2-2, and shows the control mechanism of .the grapple in the closing phase of the grapple corresponding to the phases of the grapple elements shown in Figs. 1, 4, and 12.

Figure 3 is a cross section through Fig. 1 at the plane indicated by 3-3, which shows a plan view of the grapple elements wound around a piece of pipe.

Figure 4 is a fragmentary view of the enveloping means constricted on a drill pipe. In this view the grapple is shown in a phase following that shown'in Fig. 1 wherein an upward pull Figure 5, like Fig. 1, is broken to conform to the size of the paper, and outer portions are broken away to show interior construction.

Figure 6 is a cross section taken at line 8-4 in F18. 5.

Figure 7 is a cross section taken on two planes as indicated by line 1-1 in Fig. 5.

, Figures 8 and 9, respectively, are fragmentary views of the upper and lower swivel supports of the terminals of one unit of the flexible enveloping means.

Figures 10 and 11, like Fig. 2, are phase views of the control mechanism. Figure 10 corresponds to the open phase of the grapple elements shown in Fig. 5. In Figs. 2 and 10 the grapple is supposed to be submerged in the well. The control phase shown in Fig. 11 corresponds to the closed phase of the grapple elements Figs. 1, 4, and 12, but in this case the grapple is not supposed to be submerged. This phase will occur automatically when the grapple and inclasped pipe are hoisted up in the derrick, and when operating in a dry hole.

Figure 12 is a fragmentary view showing the grapple elements constricted, but in which there is no object inclasped therein. This view indicates that phase of the grapple elements which would obtain in Fig. 1 if there were no drill pipe there to be inclasped.

Figure 13 is an elevation of an oil well derrick with conventional representations of those portions of the rotary well drilling equipment which are involved in the operation of my invention. In this view the derrick and the upper portion of s the well are shown, and Figure 14 is a lower extension of the well at the point where the drill pipe has been broken 011'. Here the upper end of the lost pipe is shown as leaning against the side of the well, and my grapple is shown in the hole as having been lowered to the'point of the break; it being understood that the pipe string carrying the grapple is continuous throughout the two views.

Figure 15 is a fragmentary detail of a pre- T ferred type of the grapple elements.

In Figures 16, 17, and 18, a modified form of the grapple is shown, in which the grapple elements are somewhat similar to the chuck blocks used to hold the drill pipe in the rotary table, and the means to control the operation of these grapple elements are the same as used for the flexible type of grapple elements.

Figures 16 and 17, respectively, are fragmentary views showing only the central portions of the grapple in closed and in open phase, and Fig. 18 is a cross section on line |8-l8 in Fig. 17. It is to be understood that the complete view of this modified grapple would include the upper continuations of Figs. 16 and 17, similar to that portion of Fig. 1 above the upper break, and a lower continuation of the pronged shell as indicated in Fig. 5 or in Fig. 14.

COOPERATIVE ROTARY Rre FACILITIES Referring to Figs. 13 and 14, the numeral 20 indicates the derrick with its floor 2|, whereon the rotary table 22 is positioned over the well 23, in which is the drill pipe 24.

The pipe string 3! comprises the round drill pipe 24, the square Kelly bar 33, and, in the present instance, my grapple 34. .This screw jointed pipe string is slidably chucked in the rotary table by means of the dogs 25, and it is swivelly carried by the swivel head 26 which, in turn, is suspended on the cable 21 over to the fall block 28 and to the crown block 23 at the top of the derrick, thence to the hoist 30.

The swivel head is connected by the hose 3| to the pump 32, so that water can be pumped, under pressure, down the drill pipe, thence to the control mechanism in the grapple, as will appear.

The above mentioned parts of the rotary rig need no further description here as they are well known to all who are versed in well drilling. It is worth while to note here, in order to understand my invention, that by means of this rotary equipment the operator can move the pipe string up and down'in the hole; he can rotate the pipe string in the well; and, with proper constriction of orifice at the bottom of the pipe string, he can maintain fluid pressure therein equal to, or greater than, the hydrostatic pressure of the fluid l9 outside the pipe string at the corresponding depth; and, moreover, any two, or all three, of the above stated conditions can be performed simultaneously if desired.

In Fig, 14 the pipe string is shown as having been lowered in the well so that the prong I III of the grapple 34 is just slightly above the lost pipe 35.

My invention includes the grapple per se and the grapple in cooperation with portions of the above mentioned-rotary equipment. The lost pipe 35 is supposed to have been originally a portion of the drill pipe 24, and to have been broken oil or otherwise disengaged therefrom.

The function of my invention as herein set forth is to recover such lost pipe.

REMOTE CONTROL MECHANISM Referring to Figs. 1, 5, and 14, the grapple 34 has an outer cylindrical shell 40 membering at the upper end with a compositively formed hub head 4|, in which is journalled a shaft 42 with double thrust bearing engagement at 43, and with a packing gland at 44.

The upper end of this shaft 42 is screwed to the drill pipe 24 at 45, which joint is typical of all the connections in the pipe string, and has a bore 46 contiguous with the drill pipe 24.

The screw jointed pipe string 31 is adapted for one way rotation in the direction which tends to tighten the joints. This direction of rotation is herein assumed to be clockwise when viewed from above, as indicated by the arrow 35.

Below the hub 4 l'the shaft 42 has a pair of oppositely positioned incised threads, of which 41 is the right hand thread, and 48 is the left hand thread, and the depending portion of the shaft carries a 'nut 49 which is slidably splined at 50 in the shell 40. This threaded portion of the shaft 42 is hereinafter referred to as the cam shaft 5|, irrespective of the hand of the threads.

Within the compositively formed nut 49, Figs. 2, 10 and 11, and on opposite sides of the cam shaft, are a pair of piston chambers of unequal bores, the smaller or high pressure cylinder 52, and the larger or low. pressure cylinder 53. In these cylinders 52 and 53 are

pistons

54 and 55 respectively. In the nut 49 is a yoke 56 having two arms 51-51 slidably splined in the nut and straddling the cam shaft 5|. This yoke is fixed to the high pressure piston 54 but is not fixed to the low pressure piston 55, as may be seen by comparing Figs. 2 and 10 with Fig. 11. slidably splined in the left hand end of the yoke 56 is a latch 58, and between this latch and the piston 54 is a compression spring 59 adapted to thrust the latch inward toward the cam shaft 5|. Similarly at the other end of the yoke the aovasas latch 6i, piston 85 and spring 82 are adapted to thrust the latch 8i inward toward the cam.

The latch 58 has a tongue 88 adaptedto-engage in the helical groove or thread 41 of the cam shaft, and the opposite latch 8| has a tongue 64 adapted to engage in the groove 48 of 'the cam shaft.

'The low pressure cylinder 58 is connected via the port 85 and depending pipe 88 (see Fig. 5) with the interior of the shell 48, so that the piston 55 continuously will be subjected to an inward thrust due to the hydrostatic pressure of the fluid I8 when the grapple is submerged as here premised.

On the other side of the cam shaft the cylinder 52 ls connected via the port 81 and pipe 88 with the passageway 88 which extends through the hub head 4i and there communicates directly with the contiguous bore I8 ofthe pipe string 31, so that the pump pressure acting on the piston 54 can be applied as required to oppose the hydrostatic pressure acting at the other end of the yoke, all of which will now be ex plained with reference to Figs. 1, 2, 5, 10, and 11.

Within the nut 49 is a cavity II, open on the yoke side, in which is a compression spring I2 adapted to bear at one end against the lug 18' fixed on the yoke, and at the other end against the nut 48.

With no pressure acting in the smaller cylinder 52, and for those cases where the inward thrust on the larger piston 55 is in excess of the thrust on the smallerpiston 54, the yoke 58, the latch 58 and the piston 58 will be fully retracted to the left as shown in Figs. 2 and 11.

In this case the latch 6i normally will be engaged with the cam shaft 5i. This phase of the yoke mechanism, as will appear, corresponds to the grappling phase of the grapple elements. and is hereinafter referred to as the closing phase referring to the grapple in its entirety.

With no pressure in either cylinder, a condition which obtains when the grapple has been withdrawn from the well, the springi! is adapted to thrust the latch 6i into engaging position on the cam shaft and to fully retract its piston 55 as shown in Fig. 11. It is to be noted here that the side spring I2 can act independently to retract the piston 54 and latch 58 when there is no pressure in the cylinder 52. This phase of the yoke' mechanism obtains also when the grapple is being used in a dry hole and also for the above mentioned conditions, as, for example, when the grapple, after having been sub-' merged in the well, has been hoisted out of the fluid Hi. This phase, then, is a special case of the closing phase of the grapple, and, as will appear, is intended as a safety measure to prevent the accidental letting go of thehold of the grapple on an object once it is closed thereon.

When the pump 32 is put in operation to force water down the pipe string to effect the required intensity of pressure in the high pressure cylinder 52, the yoke mechanism will be forced to the right to retract the latch 8i and to engage the latch 58, all as shown in Fig. 10. This phase of the yoke control mechanism, as will appear, corresponds to the opening phase of the grapple elements, and, as hereinafter used, the term opening phase refers to the grapple in its entirety.

Referring to Figs. 2, 18 and 11, the central portion of the yoke prongs are enlarged inward- 1y, thus forming a pair of lugs or stops I4 and I5 to limit the spring actuated movements of the

latches

58 and 58, respectively. I

It thus will be seen that the pistoned yoke travel is greater than the spring actuated travel of either latch. Due to this construction, the movement of the yoke from the position shown in Fig. 2 to that shown in Fig. 10 will flrst let the latch tongue 63 at the left hand end of the yoke engage in the right-hand thread 41 of the camshaft before the opposite latch becomes disengaged from the cam shaft. The opposite movement of the yoke mechanism from the phase shown in Fig. 18 to that as per Fig. 2 will first effect the engagement of the tongue 64 of the latch Si in the left hand thread 48 of the cam shaft before the latch 58' becomes disengaged from the cam shaft.

Under no circumstances obtaining here can both latches be disengaged from the cam shaft at the same time.

The nut 48 carries a depending tubular sleeve 88 which is closed at the bottom and which completely'encases the lower part of the cam shaft.

The pipe BI is axially disposed and secured in the bottom of this stem 88, and the upstanding portion thereof projects into the cam shaft to maintain rotatable and slidable contact therewith where the reduced bore 82 of the cam shaft is contiguous with the bore I8 of the pipe string. This small bore or passageway is intended as a bleeder to drain the pipe when it is being pulled out of the well. Before inserting the grapple into the well, a plug 83 is driven in the bottom of the pipe 8| for a purpose which will appear.

Fixed to the bottom of the sleeve 88 is an ex- Ro'roa AND S'rsroa Helical engagement thereof In the view of Fig. 7 are shown three concentrically disposed cylinders. The outer cylinder is the previously mentioned shell 48, the interme diate cylinder 98, and the inner one 8i.

iii

The intermediate cylinder 88 has double thrust I ball bearing engagement at 92 with the aforesaid collar 85. In the adjacent faces of the outer and inner cylinders is a pair of

helical grooves

83 and 94, respectively, in the members 48 and iii. The intermediate cylinder has a series of holes in which balls are disposed in conformity with the

grooves

93 and 94, of whichthe dotted line 98 in Figs. 1 and 5 is the trace.

Because of the functions of these three concentrically disposed members 48, 98 and iii, they are now referred to as the stator 48, the ball retainer or thrust member 88, and the rotor 9i, all of which are hereinafter more particularly set forth.

FLEXIBLE GRAPPLE ELEMENTS grapple element lie in the same radial position, I

so that the grapple elements I are held taut by means of the spring 33, and they also are disposed as elements of a cone, which means that that part of the throat I01 within the grapple elements is 01' larger diameter at the bottom than at the top, the importance of which will appear. This illustrates the open phase of the grapple elements, and corresponds to the yoke phase shown in Fig. 10 and hereinabove described.

At a point adjacent to the lower socket housings I 04 of the flexible grapple elements, the stator has an inside collar I08 which forms a seat for the grapple elements, as more particularly set forth hereinafter in connectionwith the explanation of Fig. 4.

Preferably the lower portion of the shell or stator 40 is detachable from the upper part as indicated at I09, and, depending on' circumstances, terminates in either a single prong IIO as shown in Fig. 14, or in a pair of oppositely positioned prongs III as shown in Fig. 5. Then, in some cases, lugs II2 are to be fastened on the outside of the shell to increase its resistance against being rotated in the well when the rotary table is in operation.

Loo or THE WELL RELATIVE TO THE LOCATION or rm: BROKEN DRILL PIPE The method of assembling the grapple on the pipe string, and of its insertion into a well to the proximity of the lost pipe, is similar to that of putting a drill into the well, and this portion of the work prior to the grappling operation needs no further explanation here.

It is worth while to note, however, that because the grapple can be carried on the same stands of drill pipe which were just immediately withdrawn from the well above the break, it is necessary, in connection with the log of the well, only to note the length of that part 01' the Kelly bar above the rotary table when the break occurred, and to measure the length of the broken pipe remaining on the original pipe string. Then by making the obvious allowance on the Kelly bar for the diflerence in the lengths of the grapple and of the broken pipe, the depth required to lower the grapple to the proximity of the upper end of the lost pipe can be easily determined.

OPERATION OF THE INVENTION Normally closed grapple elements The grapple elements normally will be constricted or closed as shown in Fig. 12, whether the grapple is submerged or not, and they can be opened only by the simultaneous operation of the pump 32 and the rotary machine 22.

As a starting place in the explanation of the mode of operating my invention, the assumptions are: (a) that the grapple elements are closed as in Fig. 12; (b) that the yoke mechanism is in the phase shown in Fig. 2; and (c) that the pipe string has been assembled and lowered in the Well as per Figs. 13 and 14 where the closed grapple 34 reposes slightly above the lost pipe 35.

As an optional method of procedure, the bleeder pipe 8i can be closed at the bottom by inserting the plug 83 before placing the grapple in the well. Then when the grapple is lowered in the well, the fluid I8 cannot enter the pipe string, which thus will remain empty until the pump 32 is started. This is the best procedure where a heavy drilling fluid has been used in the well.

Ormnmo rm: GRAPPLE The friction of the grapple shell 40 against being rotated in the hole will then cause the nut 49 torise on or relativeto the cam shaft. This upward movement of the intimately connected members, the nut 49, the sleeve 80 and the flange 84, compresses the spring 88 and thus raises the ball retainer or thrust member 90. This upward movement of the retainer 90 with respect to the stator 40 causes the spiral ascent of the rotor with respect to the stator, but the axial movement thereof will be double the magnitude ofthe nut movement. When the rotor 9| reaches its uppermost position relative to the stator 40, the flexible elements I00 will be drawn taut as shown in Fig. 5, with the upper terminal I and lower terminal I04 of each element disposed in the same radial plane as per Figs. 8 and 9.

With the grapple suspended above the lost pipe 35 as per Fig. 14, and with the grapple elements open as above set forth, the next step is to continue to rotate the grapple while gradually lowering the pipe string 31 in the well. This operation will cause the shell prong H0 or one of the prongs III, depending upon whether a single or multiple pronged grapple is used, to auger under the pipe 35 indicated in the full lines in Fig. 5.

Then further lowering of the grapple will force the lost pipe up into the throat I01 as indicated by the dotted outline in Fig. 5.

. At this stage of the operation of the grapple, the rotary machine should be stopped, and the pump pressure increased to force the plug 83 out of the lower end of the bleeder pipe 8|, then stop the pump. The unit pressure in the drill pipe then will be the same as in the well at the corresponding depth, and thus the drilling mud or the fluid i9 cannot enter the pipe string.

CLOSING THE GBAPPLE The pump 32 having been stopped, and with the open grapple lowered in place so that the lost pipe projects up into the throat as indicated by the dotted line 35b in Fig. 5, the grapple now can be closed by the simple operation of starting the rotary machine to turn the pipe string in its one way direction of rotation indicated by the arrow 36. The latch mechanism thus will be in the phase shown in Fig. 2 or as shown in Fig. 11, as hereinabove explained, and the she l 40 will ofier resistance against being rotated in the hole. With the concurrence of these conditions the rotation oi the drill pipe 24 with respect to the stator 40 will force the nut 49 down on the cam shaft 5| to compress the springs 81, and thus rotate the rotor 9i downwardly in its helical engagement with the stator.

This motion of the rotor will wrap the flexible elements I around the lost pipe 35 as shown in Fig. 1.

In the phase indicated in Fig. 1 the. central portion of each flexible element I 00 is spirally disposed, and the upper and lower end portions of each element are tangentially disposed with reference to the pipe 35. The upper tangential portion slopes upwardly to its bearing in the rotor socket I05, and the lower tangential por-- tion slopes downwardly to its bearing in the stator socket 104.

Because these flexible elements can transmit tensile stresses only, it is apparent that when they are disposed as in Fig. l the grapple cannot exert a heavy pull or uplift on the pipe 35 if the pipe string 31 should be pulled upwardly by the hoist 30. v The next step in the operation of my grapple then is to consolidate the flexible grapple elementson the lost pipe 35 as shown in Fig. 4. This operation can be performed by alternately lowering and raising the grapple while also operating the rotary machine to alternately release elements, the grapple'elements can be compacted in the globated form shown in Fig. 4, Where the angular contact of each element on the pipe is about 480 degrees. a

When the operation of consolidating the grapple elements has reached the stage indicated in of the flexible element from the open phase Fig.

to the closed phase Fig. 1, and the arrow I23 indicates the movement corresponding to the compacted phaseFig. 4, and the arrow H9 in Fig. 9 shows the corresponding movement of the lower tangential portion of the flexible element from the open phase to the lifting phase of the grapple. In Fig. 4 the arrows I'M and I22 indicate the opposing forces acting in each element Hill.

In the present case the three flexible elements are disposed 120 degrees apart; hence in Fig. 4 each element is crossed at the top and at the bottom by the other two elements. The efiect of this multiple crossing of the several elements is to force the links of the inner chain I00 tightly against the inclasped pipe.

The function of the spring 88 is to carry the weight of the rotor, the ball-retainer, collar, and the springs 81, and to draw the flexible elements taut when the grapple is open as in Fig. 5, where the springs 81 are relaxed.

The function of the set of six springs 81 is to exert a powerful thrust between the nut 49 and the collar 85 when the nut is forced down by the rotation of the camshaft 5| with respect to the nut, and-thereby to exert a similar thrust on the ball retainer 90. This downward pressure of the 8'! are thus adapted to maintain a self-tightening grip of the grapple elements on an object inclasped therein. 1

At this point I wish to refer again to the novel operation of the plunger ball retainer 80, the rotor 9|, and the heliciform movement of\these members with respect to the stator.

Suppose the grapple 34, when in the phase shown in Fig. 1, wherein the grapple elements are not yet fully constricted or consolidated on the pipe 35, should be rotated in clockwise direction '35 by the operation ofthe rotary machine 22. As is usually the case, the pipe 35 is supposed to carry a tool (not shown) which has become stuck fast in the formation at the bottom of the well so that the pipe 35will offer considerable resistance against being rotated in the hole. And

the size of the grapple to use in any case should be about equal to the bore in the well at the point where the original pipe string was broken, so it also will ofler considerable resistance against being rotated in the hole; otherwise the lugs I I! are to be secured on the shell 40 to effect the desired resistance.

Now, with the concurrence of the above stated conditions. here is what happens:

The rotation of the grapple with respect to the pipe 35 tends to unwind the flexible elements from the pipe at the bottom, and to wind them on at the top. But the rotation of the drill pipe with respect to the grapple forces the nut 99 down to compress the springs 81. The resilient down thrust of the springs forces the ball retainer 90 downwardly and rotatively in its helical engagement with the stator 40 to etlect vertical and angular movement of the rotor in an amount equal to twice the magnitude of the ball retainer movement.

From the above it follows that the spiral pitch of the flexible elements, at the top where they wind on the pipe, will constantly decrease until the grapple elements are fully constricted on the D D Horsrmo Ornmrrou All of the above stated operations have to do only with the opening of the grapple, with the insertion of pipe 85 into the throat of the grapple, and with the constricting or the grapple elements to secure a flrm butself-tightening grip on the lost pipe prior to the actual hoisting operation to remove the lost pipe from the well.

With the grapple elements fully constricted on the pipe in the phase shown in Fig. 1, or in any phase intermediate to that shown in Figs. 1 and 4, and also as in Fig. 4, the upward pull on the pipe string exerted by the hoist 30 will be transmitted from the shell or stator 40 to the pipe 35 through the lower tangential portions of the grapple elements.

Hence if the hoist should be put in operation to effect an upward pull on the pipe string 31 while the grapple elements are constricted as in Fig. 1, the lower tangential portions of the flexible elements will swing upward with respect to the pipe 35, and the upper tangential portions of the flexible elements will gyrate downward with respect to the stator, so that the grapple shell will move upward with respect to the pipe until a position is reached whereby the vertical components of the tension stress in the lower tangential portions of the flexible elements is equal to the weight of the pipe 35, whence the lost pipe can be pulled out of the well.

Depending upon the circumstances obtaining pipe 35, plus the force required to dislodge the drill (not shown) which will be'stuck fast at the bottom of the well.

ANNULAB SUrPoa'r ma rm: Gmrnl Emnsn'rs In other cases, where the inside collar I08 at the stator terminals is employed, this collar forms an annular seat which is thus adapted to engage the lower portion of the compacted or globated grapple elements as shown in Fig. 4.

Here the upward pull of the hoist required to dislodge the lost pipe, and to remove it from the well, is distributed over the entire bottom annular surface of the constricted and globated flexible grapple elements, and thence through the frictional contact of these elements on the pipe 3!.

Thus where the inside collar I0! is employed, the strength required in the flexible elements is governed by the torque developed between the stator and rotor, and not by the vertical force required to pull the lost pipe out of the well.

ALTERNATIVE TYPE Fmrxrsm Gmrmr Emurm'rs In some cases the flexible elements will be of specially constructed chains as shown in Fig. 15, where the links H4 are made of square stock having barbs H5 on the outside faces, and the links H3 are of round stock. In this chain the barbed links and the plane links are alternately disposed. The sharp corners and the barbs of the links Ill are intended to increase the frictional engagement of the grapple elements on the inclasped pipe.

ALmNA'rrva Foam or Gssrru:

The grapple shown in Figs. 16, 17, and 18 has an outer shell la, the wall of which is thickened at I30, where downwardly and inwardly sloping channels I3I are formed. In these sloping grooves are slidably splined blocks or grapple elements I32, having links I33 pivoted thereto at I34, which in turn are also pivoted at I35 to the thrust plunger 90a.

The plunger 90a. has thrust engagement at Ma. with the collar 85a.

In this block type of grapple the means to control the operation of the grapple elements are similar to those for the flexible grapple element type, so the cam shaft ila, the sleeve 800., spring 88a and springs 81a, all of which are shown in Figs. 16, 1'7, and 18, are identical in both types of grapple. Moreover, a section 60. in Fig. 17 is similar to section 6 in Fig. 5, and the latch mechanism on the cam shaft and all other parts of the two grapples are similar.

. The grapple blocks I 32 have teeth I36 adapted to engage the drill pipe 350 in a manner similar to that appertaining to the dogs 25 as per Fig. 13, which is well known to all versed in well drilling. With obvious deviation,'the method of operating the block type grapple is similar to that hereinabove set forth for the flexible type grapple, so that the one-way rotation of the cam shaft in the shell will effect the upward and downward movement of the grapple elements or blocks I32, the direction of motion being governed by the righthand or left-hand engagement of the latch mechanism with the cam shaft, which can be selectively controlled by means of the pump 32.

Having thus described my invention, I claim:

1. A grapple which comprises: a shell; a cam shaft with thrust bearing engagement in the upper end of the shell, and adapted as a hanger for the required strength to carry the weight of thethe support of the grapple; a fluid pressure operable latch mechanism on the cam shaft; a plurality of grapple elements in the lower end of'the shell; the disposition of the aforesaid parts whereby to control the opening and the closing of the grapple elements as governed by the rotation of the cam shaft with respect to the shell and the control of the fluid pressure in the latch mechanism.

2. In the art of grapples for submerged operation, such as occurs during the construction of oil wells, a remote controlled grapple which comprises: a shell or stator; a plurality of grapple elements in the shell; a rotatable cam shaft iournaled in the shell; a two cylinder pistoned latch mechanism on the cam shaft; means to continuously apply the hydrostatic well pressure in one of the latch cylinders, and means to apply pump pressure in the other latch cylinder, whereby to control the selective engagement of the latch on the cam shaft, and means to rotate the cam shaft relative to the stator, thus to control the operation of the grapple elements.

3. In a grapple: a shell; a plurality of grapple elements concentrically disposed in the shell; a cam shaft Journaled in the shell, and with a right-hand thread and a left-hand thread thereon; a nut on the threaded cam shaft; a latch mechanism in the nut adapted for selective engagement in the right-hand thread and/or lefthand thread of the cam shaft, and remote control means to govern the movement of the latch mechanism adapted for the selective opening and closing of the grapple elements.

4. In combination: the string of drill pipe; the hoisting mechanism; the rotary machine and the pressure pump facilities as used in a rotary well drilling rig, and a grapple which comprises: a shell; a cam shaft Journaled in the shell, adapted for attachment to the string of drill pipe to swivelly support the shell thereon; a fluid pressure operable latch mechanism on the cam shaft; a grapple element or grapple elements within the shell, and means to control the operation of the grapple contingent on the rotation of the cam shaft and the regulation fluid pressure via the drill pipe.

5. In the art of oil well grapples and in cooperation with the well-known rotary drilling rig, a grapple which comprises: a pair of concentrically disposed and helically engaged cylinders, relatively a shell or stator and a rotor; a plurality of flexible grapple elements suspended from the stator to the rotor; a cam shaft journaled in the shell; a latch mechanism carried as a nut on the cam shaft; and means to control the operation of the grapple elements as governed by the reciprocal movement of the nut on the cam shaft.

6. In a grapple: three concentrically disposed cylinders, relatively a shell or stator, a ball retainer plunger and a rotor; heliciform ball bearing engagement of these three cylinders whereby the magnitude of the rotor movement relative to the stator is twice the magnitude of the movement of the plunger relative to the stator; a plurality of flexible elements conically disposed with reference to the axis of the grapple, and suspended from the stator to the rotor; and means to control the movement of the plunger relative to the stator, thus selectively to open and close the grapple elements.

7. In a grapple: three concentrically disposed cylinders, relatively a shell or stator, a ball retainer and a rotor; heliciform ball bearing engagement of these three members; a plurality of flexible grapple elements, with the lower end of each swivelly disposed in the stator, and the upper end of each swivelly disposed in the rotor; a shaft with\thrust bearing engagement in the stator, and a depending portion thereof with a right-hand and a left-hand screw thread; a nut on the shaft; a latch mechanism in the nut adapted for selective engagement in said threads; means to control the rotation of the shaft relative to the stator, and means to control the operation of the latch mechanism.

8. A grapple which comprises: a pair of concentrically disposed cylinders, relatively an outer stator: and an inner rotor; a,plurality of flexible grapple elements with lower terminal support in the stator, and upper terminal support in the lower end of the rotor; heliciform engagement of rotor and stator, and means to' control the gyratory movement of the rotor in the stator, whereby to draw the grapple elements taut in conical configuration to open the grapple upon the upward movement of the rotor, and to constrict the grapple elements on the downward movement of the rotor.

9. A grapple which comprises: a pair of concentrically disposed cylinders, relatively a stator and a rotor; heliciform engagement of rotor within the stator; a plurality of flexible grapple elements suspended from rotor to stator; an annular collar within the stator adjacent the stator terminals of the flexible elements, and means to control the movement of the rotor relative to the stator whereby selectively to draw the grapple elements taut in conical disposition, and to constrict them within and above the said collar.

10. A grapple which comprises: a shell; acam shaft with thrust bearing engagement in the upper end of the shell; a nut on the cam shaft: a fluid pressure operable latch mechanism in the nut, adapted for selective engagement with the cam shaft; a plurality of slidably splined grapple elements in the lower end of the shell; and means to control the movement of the grapple elements with respect to the shell as governed by the rotation of the cain shaft in the shell and the control of the fluid pressure in the latch mechanism.

11. A grapple which comprises: a shell; a plurality of slidably splined grapple elements in the lower end of the shell; a shaft thrust journaled in the upper end of the shell, with a right-hand and a left-hand cam thereon; a latch mechanism carried as a nut on the cam shaft; means to controlthe selective engagement of the latch mechanism on the cam shaft, and means to rotate the cam shaft relative to the shell whereby to open and close the grapple.

CLARENCE A. KELSO.