US2681821A

US2681821A - Thread lock lift plug

Info

Publication number: US2681821A
Application number: US97185A
Authority: US
Inventors: Weldon L Medders
Original assignee: Houston Oil Field Material Co Inc
Current assignee: Houston Oil Field Material Co Inc
Priority date: 1949-06-04
Filing date: 1949-06-04
Publication date: 1954-06-22
Anticipated expiration: 1971-06-22

Description

June 1954 w. L. MEDDERS THREAD LOCK LIFT PLUG 3 Sheets-Sheet 1 Filed June 4, 1949 IN V EN TOR. Weldon bMeddem' 47/ 1" ?&

ATTORNEY J1me 1954 w, L. MEDDERS THREAD LOCK LIFT PLUG 3 Sheets-Sheet 2 Filed June 4, 1949 IN V EN TOR. WeldOn L Meddem yam ATTOQNE Y June 22, 1954 w. L. MEDDERS 2,681,821

THREAD LOCK LIFT PLUG Filed June 4, 1949 3 Sheets-Sheet I5 We/oon L. Meoaem INVENTOR.

A TTOR/Ve) Patented June 22, 1954 THREAD LOCK LIFT PLUG Weldon L. Medders, Houston, Tex., assignor to Houston Oil Field Material Company, Inc., Houston, Tex., a corporation of Delaware Application June 4, 1949, Serial No. 97,185

9 Claims.

This invention relates to a locking type of lift plug for use in manipulating pipe, and more particularly relates to a thread lock lift plug.

The present invention is capable of use under various circumstances but is particularly useful in connection with well drilling operations where the drill pipe is lowered and removed from the well bore. In the use of what is known as flush joint drill pipe, where the outer surface of the threaded pipe connection is flush so as to provide less friction to the circulation of drilling mud in the well bore and so as to permit the pipe to be moved through valves and blow-out preventers because of its uniform outer diameter, considerable difficulty is encountered in supporting the pipe with the hoisting equipment and the practice has been developed of inserting lift plugs in the upstanding end of the pipe so as to provide an outstanding shoulder to permit supporting of the pipe in the elevator or slips.

It is customary practice to provide one such lift plug for every three joints of drill pipe in lowering the pipe into or removing it from the well bore. These lift plugs must be screwed tightly into the pipe in order that the greatest care is exercised to prevent unscrewing of the plug and therefor the lift plug is usually made up or wedged tightly into the pipe. With the plugs now in use the general practice is to utilize a heavy sledge hammer in making up the lift plug into the threads of the pipe and the reverse operation is performed in knocking the plug loose. There have been instances, however, where such plugs have become loosened and permitted the pipe to drop into the hole.

It is a feature of the invention to provide such a lift plug which may be made up or released by hand in a minimum of time and labor.

It is an object of the invention to provide a lift plug of minimum parts and which is rugged and which may be easily and economically manufactured for all sizes of pipe and which will automatically lock in position but which is capable of being readily released for removal.

It is an object 'of the invention to provide a lift plug which will wedge in the threads of the pipe by thread means or securing means in the plug of a pitch different from the threads in the pipe, but will readily. release by the particular releasing operation. i

It is a further feature of the invention to provide a lift plug possessingthe above advantages which may be connected to the pipe so as to provide a shoulder below which the hoisting mechaw nism may be connected so as to lower or raise the pipe.

Other and further objects will be apparent from the following description taken in connection with the accompanying drawings where like references designate like parts throughout the several views and Where Figure 1 is a plan view, with parts broken away, illustrating the lift plug and Wrench therefor in position to either thread or unthread the plug from the pipe,

Figure 2 is taken along the line 2-2 of Figure 1 and is a side elevation, partly in section, illustrating the lift plug threaded into a section of pip Figure 3 is a side elevation illustrating a preferred form of my lift plug,

Figure 4 is a fragmentary detail of the special wrench taken along the line 4-4 of Figure 1,

Figure 5 is a plan view of a modification of my lift plug and wrench, and is generally similar to Figure 1,

Figure 6 is taken along the line 6-6 of Figure 5 and illustrates a side elevation, partly in section, of the modified form shown in Figure 5,

Figure '7 is a side elevation of the modified form of lift plug, and

Figure 8 is a diagrammatic view of typical hoisting equipment secured about a pipe to be lifted and engaging the lower shoulder of the lift plug of the invention.

Referring to the drawings, and particularly to Fig. 2, the lift plug generally designated by the numeral I0 is illustrated as connected to the upper section of a pipe l2, which pipe is of the flush joint type of pipe where the outer periphery I4 is of uniform diameter. The upper end of the pipe is formed with the threaded box I6 which receives'a complementary threaded pin end (not shown) of the next section of pipe when the string of pipe is connected together.

The plug 10 has the enlarged collar portion or body l8 provided with the lower shoulder 20 to make up against the end 22 of the pipe l4 when the plug Il is threaded in the threaded box l2 of the pipe [4.

The plug H] has a unitary pin II which is formed of a first pin member 25 which extends from the body or collar portion It and a second pin member 36 which is positioned adjacent the first pin member to providea continuation of the first pin member 26 and form the unitary pin ll. The firstand

second pin members

26 and 36, respectively, arethreaded at 24- and 38, respec- 1 tively, to. form, acontinuous thread which may 3 be made up or threaded into the threaded box I6 of the pipe l2.

In order that the first and

second pin members

26 and 36, respectively, may movably be secured together and by separation of the first and

second pin members

26 and 36, respectively, of the unitary pin 1 I provide a wedging action with the threaded box It, the plug I is provided with a longitudinal cylindrical bore 28 therethrough and has a relatively fine threaded portion 30 at its upper end with respect to the threads I6 and 24. A cylindrical shaft or shank it having a complementary threaded portion 34 to the threads 30 proximate its upper end isthreaded into the bore 28. The second pin member 36 is integral with the lower portion of the shank 32 and is, in efiect, an enlarged circumferential flange having the externally threaded portion 28 thereon, as previously 7 described. Thus the threaded pin l l is made up of two relatively movable portions held together by threads of a pitch difierent from those threads on the pin l I of the lift plug. The lower inner end of the 'bore 28 of the first pin member 26 is chamfered at 4B, and the upper extending end 42 of the shank 32 has the flattened sides or wrench fiats 44, both for a purpose to be described later.

In order that the lift plug may be threaded into or unthreaded from the pipe, the upper portion of the collar 18 may be straddle milled to provide the wrench flats or longitudinal shoulders 46 which may be substantially in alignment with the wrench flats 44 of theextension 42 of the shaft 32. A wrench 58 having the jaws 50 adapted to engage the wrench flats 46 of the collar 18 has a plate member .52 secured across the jaws by means of the cap screws 54. The wrench plate member 52 has a slot 56 of generally elongated configuration, the slot being in alignment with the jaws and adapted to fit over the upper extension 42 of the shank32 and engage the wrench fiats 44 of the former. As illustrated a ball crank handle may be disposed at the end of the wrench handle 58.

It is manifest that when the wrench is in the position illustrated in Figs. .1 and 2, the first and

second pin members

26 and 36, respectively, forming the unitary pin II, will be held as a unit whereby the device may be turned as a unit.

When the plug I0 is threaded into the pipe l4,

as illustrated in Fig. 2, and the wrench removed, the hoisting equipment; such as illustrated in Figure 8, as later described, may engage the shoulder 29 of the plug I0 in order that the pipe i2 may be raised or lowered. The plug is automatically locked into position inasmuch as the plug and shank must rotate as a unit in order to prevent Wedging of the threaded areas due to the difference in pitch of the threaded areas effectuating a wedging thereof and thereby effec tively preventing the lift plug from uncoupling. It is manifest that the threaded area 38 will be subject to more friction than the interface of the lower chamfered end of the pin' extension and the upper face of the radial extension of the shank, thus the elements of the plug will not turn as a unit due to friction; however, "in practice, in cutting the threads 24 and 34' the shank and plug may be hand made up and a shim may be placed in a portion of such interface in order to provide a ready release between these faces. In practice it has been found that a .063 inch semi-hard brass shim is effective for fthe purpose. The imperfect thread may then be turned down. If desired that portion of the shaft 32 immediately above the lower radial flange may be slightly enlarged (not shown) to provide a close fit to prevent dirt or debris from entering the bore 28. Thus an effective and automatic lock of the lift plug is secured. In

order to unthread the plug, the wrench may be inserted as illustrated in Fig. 2 and the shank and plug will rotate as a unit thereby easily and readily unthreading the plug.

It is believed that the manner of operation and use of this plug is apparent from the above description. By way of summary, however, the

plug is assembled as illustrated in Figs. 2 and 3 and maybe threaded "by the wrench by hand into the top portion of a string of pipe to be manipulated. The special wrench threads the plug into the pipe as a unit. The wrenchis then removed and the pipe may be readily lowered or raised by means of hoisting equipment connecting to the pipe just below the enlarged collar portion of the plug. As best seen in Figure 8, a conventional elevator 10 is secured to the traveling block 12 which is raised and lowered by means of the cable 14 from the top of the derrick 'by rig equipment, both not shown. A conventional mud connection 16 is illustrated for circulation of drill fiuid, but no further description of such hoisting equipment is deemed necessary as any conventional hoisting equipment or arrangement may be used, the hoisting equipment as such forming no part of the present invention. The plug will be automatically locked inposition inasmuch as the difference in pitch of the threaded areas securing the plug together will cause a wedging in the threaded areas thereby effectively preventing untimely release of. the plug. After use and it is desired to remove the plug, the wrench may be positioned as illustrated in Figs. '1 and 2 and the plug unthreaded from the pipe by hand.

It will be understood that any type of squared portion or multisided configuration of the plug and shaft extension may be utilized in connection with a complementary wrench in order to provide turning movement to the component parts of the plug as a unit.

A modified form of the plug and wrench is shown in Figs. 5 to 7. In this embodiment the wrench flats '46 are omitted from the collar l3, and the plug has a radial bore 60 to receive the complementary pin 62 secured to the lug 64 depending from the wrench 5'8. Here the jaws of the wrench are adapted to engage the wrench fiats 44 of the extension 42 of the shank 32. .Thus the wrench will thread or unthread the plug ID as a unit into or out of the box portion of a pipe. The threads 30 inthe upper portion of the bore 28 and the complementary threads 34 on the shank 32 are relatively faster or coarser than the

threads

16, 24 and 38 thereby providing the wedging action. The remainder of the plug and wrench are identical with the preferred form and the manner of operation is the same.

Although I have illustrated relatively fast and coarse'threads to secure the shaft 32 to the lift plug as being preferable, it is manifest that the shaft may be secured to the plug in other ways; for example, the shaft may have a spiral groove thereon of a number of turns per unit different from the threads on the pin member/and the plug may be radially counter-bored and a pin inserted thereinto project into the bore to provide a complementary key to the groove in the shaft. While it may be more diflicult to manufacture, a ball might be utilized in place of the key, It is important that the means to make up the component parts be of a pitch different from the threads on the pin member of the plug.

While the invention has been described in detail as applied to a flush joint pipe, it seems obvious that it may be utilized under various other conditions.

Broadly my invention contemplates a lock lift plug including relatively movable component parts secured together by thread means of a pitch different from threads on the pin member whereby the lift plug is automatically locked in position, and may only be released by turning the plug as a unit.

I claim:

1. A locking lift plug comprising, a body, an externally threaded first pin member extending from such body, an externally threaded second pin member movably secured to said plug, said first and second pin members forming a unitary externally threaded pin, and securing means of a pitch different from threads on said unitary pin securing such second pin member to such plug.

2. A locking lift plug for pipe comprising, a body, a first threaded pin member on said body, a bore through said body and said first threaded pin member, a shaft positioned in said bore, a second threaded pin member on said shaft, said first and second threaded pin members disposed in abutting relationship thereby providing a unitary threaded pin adapted to engage threads in said pipe, and thread means in said bore and on said shaft of a pitch different from threads on said first and second threaded pin members threadedly securing said shaft in said bore.

3. A locking lift plug for pipe comprising, a body, a first threaded pin member on said body, an axial here through said body and said first threaded pin member, a shaft positioned in said axial bore, a second threaded pin member on said shaft, said first and second threaded pin members disposed in abutting relationship thereby providing a unitary threaded pin adapted to engage threads in said pipe, and thread means in said axial bore and on said shaft of a pitch different from threads on said first and second pin members threadedly securing said shaft in said axial bore.

4. A locking lift plug comprising, a body, an externally threaded first pin member extending from said body, an externally threaded second pin member movably secured to said plug, said first and second pin members forming a unitary externally threaded pin, securing means of a pitch different from threads on said unitary pin securing such secondpin member to such plug, and means on said body and associated with said second pin member to turn the plug as a unit.

5. A lift plug comprising, a body, an externally threaded first pin member extending from said body, an externally threaded second pin member movably secured to said plug, said first and second pin members forming a unitary externally threaded pin, securing means of a pitch different from threads on said unitary pin securing such second pin member to such plug, and means on said body and associated with such second pin member to turn the plug as a unit into or out of pipe to be manipulated, such last mentioned means including a handle having portions thereon to engage said body and said means associated with such second pin member so that turning of the handle screws or unscrews the plug into or out of said pipe.

6. A locking lift plug for pipe comprising, a body, an externally threaded first pin member extending from such body, an externally threaded second pin member movably secured to said plug, said first and second pin members providing a continuous externally threaded pin, securing means of a pitch different from threads on said continuous pin securing such second pin member to such plug, and means on such body by which hoisting mechanism may be secured so as to lower or raise the pipe when the plug is threaded to the pip 7. A locking lift plug for pipe comprising, a body, an externally threaded first pin member extending from such body, an externally threaded second pin member movably secured to said plug, said first and second pin members forming a continuous externally threaded pin, and means movably securing such second pin member to said plug whereby relative movement of said pin members effects a separation of such pin members thereby wedging such continuous pin to such pipe when the plug is threaded thereto.

8. A locking lift plug for pipe comprising, a cylindrical body, an annular shoulder at the lower end of the body, a reduced-diameter externally-threaded first pin member extending from said body below the shoulder, an externallythreaded pin member movably secured to such plug, such first and second pin members forming a unitary externally-threaded pin, means movably securing such second pin member to said plug whereby relative movement of said pin members effects a separation of such pin members thereby wedging such unitary pin to such pipe when the plug is threaded thereto, hoisting mechanism secured about the pipe when the plug is threaded thereto engaging the annular shoulder so as to lower or raise the pipe.

9. A locking lift plug for pipe comprising, a cylindrical body, an annular shoulder at the lower end of the body, a reduced-diameter externally-threaded first pin member extending from said body below the shoulder, an axial bore through the body and the first pin member, a shaft positioned in the axial bore, a second threaded pin member on the shaft, said first and second pin members disposed in abutting relationship and providing a unitary threaded pin adapted to engage threads in said pipe, thread means in the axial bore and on the shaft different from threads on the first and second pin members threadedly securing the shaft in the axial bore, and means on the body and on the shaft to thread the plug as a unit into or out of the pipe to be manipulated, such last-mentioned means including a handle having means thereon to engage the body and the means on the shaft so that turning of the handles screws or unscrews the plug into or out of the pipe, hoisting mechanism secured to the pipe below the plug engaging the shoulder so as to lower or raise the pipe when the plug is threaded to the pipe.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,518,716 Waugh Dec, 9, 1924 1,532,150 Olson Apr. 7, 1925 2,534,662 Froom Dec. 19, 1950 2,562,327 Moore July 31, 1951