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Publication numberUS2113647 A
Publication typeGrant
Publication dateApr 12, 1938
Filing dateJan 13, 1936
Priority dateJan 13, 1936
Publication numberUS 2113647 A, US 2113647A, US-A-2113647, US2113647 A, US2113647A
InventorsDavidson William D, Guglielmo Tremolada
Original AssigneeEmsco Derrick & Equip Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Rotary swivel
US 2113647 A
Abstract  available in
Images(3)
Previous page
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Claims  available in
Description  (OCR text may contain errors)

A N 112, 1933. W. D." DAVIDSON ET AL 2,113,647

ROTARY SWIVEL Filed Jan. 13, 1936 3 Shets-Sheet J [/v 7095 MM. L 04M 0. 0A woso/v GUGL/ELMO TREMOLA DA Md W 'April 12, 1193:. w. D. DAVID-SON ET A ROTARY SWI VEL Filed Jan. 13, 1936 3 Sheets-Sheet 2 JA/VENTO W/LL/AM D. DAl/Y o/v GUGL/ELMO 7725 LADA A rromve v April 1E2, 193%. w. D. DAVIDSON ET AL ROTARY SWIVEL Filed Jan. 13, 1936' 5 Sheets-Sheet 5 Patented Apr. 12, 1938 UNITED STATES ROTARY sr.

Application January 13, 1936, Serial No. 581568 1% Claims.

Our invention relates to rotary swivels which have a particular utility in the oil producing industry. In the detailed description which is to follow, our invention will be described in con- 5 nection with such use.

In order that the features and advantages of our invention may be better understood brief reference will be made to the oil producing lndustry.

As illustrated in Fig. l of the accompanying drawings, which shows a utility view illustrating the use of our invention, it is common practice to drill oil wells by means of a rotary bit I l secured to the lower end of a string of drill pipe l 2. The

drill pipe l2 extends to the surface of the ground and has a kelly it connected to its upper end which extends through a rotary machine l5 and is engaged and caused to rotate by the table It.

In accordance with standard practice, aswivel ll,

to which type of apparatus our invention relates,

is connected to the upper end of the kelly Hi.

This swivel is supported by means of a travelling block Hi, the hook of which is illustrated in Fig. 1.

During drilling operations it is common practice to pump rotary mud downward through the drill pipe, which rotary mud issues from openings such as indicated at 20 in the bit H, and this rotary mud thereafter flows upward through the well to the surface of the ground and performs the valuable functions of carrying the cuttings to the surface of the ground, preventing cave-ins of the walls of the well, and when an oil formation or gas formation is penetrated in holding back the pressure. This rotary mud is pumped by means of a slush pump 2i and flows through a stand pipe 22 and a flexible hose 23 to the swivel H.

In the present advance stage of oil well drilling, wells are drilled very deep, it being common practice to reach 8000 and 9000 feet, and it is therefore necessary that the swivel be constructed to support enormous loads. It is likewise necessary to pump the rotary mud under relatively high pressures. Due to the fact that this rotary mud contains, as a large percentage of its volume,

abrasive particles, the parts of the swivel must be designed so that any parts which wear can be easily replaced and so that suitable packing of relatively long life, and which may be readily replaced, is provided. It is furthermore desirable from the standpoint of efiiciency that the swivel be designed so that in case repair is necessary the parts may be quickly taken apart, the repair or replacement work done, and then quickly assembled, in order thatthe well will not be taken out of service for any more than a minimum length of time.

It is the principal object of our invention to provide a swivel which is designed from the standpoint of construction and also of operation to 5 meet the present and future requirements of the oil drilling industry.

It is an object of our invention to provide a rotary swivel in. which the different bearings which support the rotating parts may be readily 1o removed, repaired, and replaced in a minimum length of time.

It is an object of our invention to provide a rotary swivel in which the bearings will be provided with ample and eflicient lubrication. 15

It is an object of our invention to provide a rotary swivel inwhich the stuffing box between the stationary and moving parts is so supported that it may be readily removed, repaired, and reinstalled. go

It is an object of our invention to provide a rotary swivel in which the stuffing box between stationary and moving parts is so positioned that it will be efliciently cooled, thus increasing the life of the packing. 25

It is an object of our invention to provide a rotary swivel in which the wash pipe which c0- operates with the stumng box and which is ordinarily subjected to considerable wear may be readily and quickly replaced, thus keeping the 30 rotary swivel out of service for but a minimum of time.

The foregoing objects set forth the more general and comprehensive objects and advantages of the invention. There are, however, many features and objects which reside in certain preferred details of construction and arrangements of parts and which are too numerous to set forth at this point, but 'will be pointed. out in the course of the detailed description of our invention which 40 is to follow.

Referring to the accompanying drawings which show preferred and alternative forms of our invention:

Fig. 1 is a utility view (which has already been 45 described) illustrating the utility of our invention.

Fig. 2 is an elevational view partly in section showing the preferred form of our invention.

Fig. 3 is a sectional view taken on the line 3- -3 50 of Fig- 2.

Fig. 4 is a sectional view taken on the line fl--:l of Fig. 2.

Fig. 5 is a fragmentary elevational sectional view taken on the line 5-5 of Fig. 2. 55

Fig. 6 is a fragmentary vertical sectional view through the stuffing box of our invention and is taken on the line 65 of Fig. 3.

Fig. 7 is a fragmentary perspective view of a lantern or spacer part employed in the stumng box of our invention.

Fig. 8 is afragmentary view similar to Fig. 6, and showing an alternative packing arrangement which may be employed in our invention.

Referring to the drawings in detail, and particularly to Figs. 2 to 5 inclusive, we provide the swivel I! with a body consisting of an upper section 30 and a lower section 3 l. The upper section 39 consists essentially of a cylindrical portion 32 having an outwardly extending flange 33. The lower section 3i is essentially of cup shape having a lower wall 34, a side Wall 35, and an upper flange which engages the flange 33 on the upper section 33. These two parts are. secured together by bolts 3'! which extend through openings provided in the flanges 33 and 35 and. in the bottom wall These bolts have nuts 3% on the lower ends thereof and thereafter the two sections 38 and 35 may be separated by removing the nuts 38 from the bolts 3'71. The swivel is supported by means of a stirrup or yoke dii which is pivotally mounted on pins 4| secured to the upper section 313.

Rotatably supported within the body is a spindle 43, the lower end of which is connected to the kelly 54. The spindle 13 is rotatably supported by a bearing arrangement which will now be described. For carrying the weight of the spring of drill pipe there is provided a thrust bearing M. This thrust bearing is supported by the lower section 35 of the body which has a horizontal face d5 on which the thrust bearing rests and has a cylindrical concentric shoulder #55 which holds the thrust bearing in a concentric position. The spindle 53 has an outwardly extending shoulder 48 which engages the thrust bearing 4 and by means of which the weight of the drill pipe is transferred to the thrust bearing.

For the purpose of restraining the spindle 43 from radial or lateral movement, a lower radial bearing 53, and an upper radial bearing 5| are provided. The lower radial bearing surrounds a cylindrical face 53 of the spindle 53 and engages an inner cylindrical face 54 provided in the lower part of the upper section 33. There is a shoulder 55 on the spindle 43 below the cylindrical face 53 and there is a shoulder 56 above the cylindrical face 54 of the section 38. The upper radial bearing surrounds a cylindrical face 59 provided by the spindle 43 and engages an internal cylindrical face 60 provided at the upper end of the section 30. There is a shoulder 6| provided by the upper section.38 at the lower end of the internal cylindrical face 68. To prevent relative vertical movement between the spindle 43 and the body we provide a hold-down bearing 63 which is positioned between the shoulder 48 and a shoulder 64 provided by the upper section 30 immediately below the internal cylindrical face 54. g

The bearings 44, 50, and 63 are all removable from the lower part of the body and the bearing 5| is removable from the upper part thereof. This particular arrangement of the bearing enables the upper section 30 to be relatively reduced in size and at the same time amply strong. and enables the rotary swivel as a whole to be made considerably smaller than the swivels in use at the time our invention was developed.

A seal is formed around the lower end of the spindle 43 by means of a lower cover 36 which is secured to the lower section 3| and which carries suitable oil seal parts 61. A seal is formed at the upper end of the spindle 43 by means of a swivel body cover 58 secured to the upper section 38 by studs 69, and which carries a suitable oil seal member l0.

The body is designed so that it may contain ample lubricant for the various bearings. The upper section is provided with an opening through it which is of sufficient size to receive the spindle 43 and at the same time provide an oil chamber 12 which carries ample lubrication for the radial bearings 50 and 5|. The lower section 3| is cup shaped, as pointed out heretofore. It therefore provides a relatively large chamber 13 which carries a larger volume of lubricant so that the thrust bearing which carries the weight of the drill pipe may receive its proper amount of lubrication. The lubricant is delivered to the chambers l2 and 13 which cooperate to provide the lubricant chamber of the swivel through a passage 14 which is formed in thecylindrical wall 32 of the upper section 30. The lower end of the passage 74 is connected to the chamber 33, and the upper end thereof is connected to an opening 15 formed in the swivel body cover $8 and which is closed by a suitable plug l5. This filling passage is extended relatively high in order that the oil level may be maintained above the upper radial bearing 5|.

The chamber 13 is designed so that the thrust bearing did is at the inner part thereof. When the parts are in operation the centrifugal force tends to throw the oil outwardly. It will be noted, however, that the chamber 13 is provided with an annular pocket 18 which is below the moving parts of the thrust bearing 44. As shown in Fig. 4, the chamber 13 is divided into sections by means of the inwardly extending webs i9 and the walls 38 which define the passages through which the bolts 31 extend. The pocket i8 which is thus divided into sections provides a sediment receptacle into which any sediment or foreign matter in the oil may settle out of circulation and not be, returned to the bearings. When the lower section has been removed from the upper section the interior of the chamber 13 is readily accessible and the pocket 18 may at that time be cleaned.

Secured to the upper end of the spindle 43 is a wash pipe 85. The wash pipe has a lower end 86 which extends into a counterbore of the spindle, and it also has a flange 81 through which a securing stud 88 extends. The wash pipe 85 therefore is secured to the spindle 43 and rotates therewith. The wash pipe 85 is at its upper end in communication with a gooseneck 90 and to prevent leakage between the rotating wash pipe 85 and the non-rotating gooseneck 90 a stuillng box 9| is provided.

Extended upward from the swivel body cover 68 is a plurality of arms 92 which supports a ring 93 at the upper end. The arms 92 and the ring 83 constitute what we term a bridge". best shown in Fig. 6, the ring 93 has a central opening 95 and a counterbore 96. Supported by the ring 93 is a stuffing box housing 91. The stufling box housing 91 has a flange 98 at its upper end which rests in the counterbore 96 and has a cylindrical wall ,99 immediately therebelow I00 through which securing studs llll extend. 75

The engagement of the faces forming the depressions I with the studs IOI prevents the stufling box housing from rotating. The lower end of the stufiing box housing is provided with heat radiating fins I03. The gooseneck'90 has a flange I 04 which rests above the ring 93 and engages the upper end of the stufling box housing 91. The studs IOI extend through openings in the flange I04 and the parts are secured together by nuts I05 screwed onto the upper ends of the studs. When it is desired to disassemble the stufiing box arrangement the nuts I05 are removed, the gooseneck is removed by moving it upward, and thereafter the stuffing box housing may be removed bypulling it upward through the opening 95. This exposes the wash pipe 85 and permits its removal. It will'be seen that these parts may be disassembled and assembled without disturbing the spindleor body of the rotating swivel. Other than described, the gooseneck 90 is made in accordance with standard practice and the rotary hose 23 is connected thereto as shown in Fig. l.

In the preferred form of our invention we employ a packing arrangement as illustrated in Fig. 6. An alternative form of packing which may be used is illustrated in Fig. 8.

Referring to Fig. 6, the stuffing box housing 91 is of larger internal diameter than the external diameter of the wash pipe 85. The lower end of the stuflingbox housing 9?, however, has an inwardly extending wall IN. The flange Hi l of the gooseneck 90 is provided with a passage of substantially the same diameter as the space provided within the stuffing box housing 91 and at the upper end thereof there is a shoulder I09. There is therefore provided around the upper end of the wash pipe 85 a packing chamber I09 in which the preferred form of packing of our invention is placed.

The upper face of the inwardly extending wall I0? is provided with an annular channel IIIl, which channel has downwardly converging walls v which blend into a curved bottom wall. Placed in the packing chamber immediately above the inwardly extending wall I01 and extending into the channel I I0 is a packing element I II which is completely annular or ring shaped and which is of V-shaped or chevron shaped cross-section. The packing element has a pair of upwardly diverging walls II2 which have end faces II I which are substantially of cylindrical shape so that the end walls III engage the outer wall of the wash pipe 85'and the inner wall of the stuffing box housing 97. Placed above the packing element I II is a spacer or lantern IIB. As shown best in Fig. '7, the spacer II6 has a lower annular part of V-shaped cross-section III which fits against the upper faces of the walls I I2 and has an upper annular portion II8 which provides an upwardly exposed channel I I9 which is of substantially the same shape as the channel H0. The portions I I 1 and I I8 are connected together by a relatively thin vertical wall I having openings I2I therein.

- The upper section I I8 has vertical channels I23 cut in the opposite sides thereof to permit free passage of grease. Placed above the spacer II 6 is a plurality of packing elements I26 which are of the same construction as packing element III. Placed above the packing elements I26 is a spacer or lantern I21 which is of the same construction as the spacer or lantern IIB. Placed above the spacer I2! is a pluralityof packing elements I29, each of which is of the same construction as the packing elements I II and I26. Placed above the packing elements I29 is a follower I30 which is of V-shaped cross-section at its lower end so that it fits in between the walls of the uppermost packing element I29 tending to hold it against the walls defining the packing chamber I09. Compressed between the follower I30 and the shoulder I08 is a spring I 32. The purpose of this spring I32 is to force the entire packing construction starting with the follower I30 vdownward against the inwardly projecting wall I 01 in order that the packing elements will be held in proper packing position; namely, with theend faces I Id of the side walls II2 of the packing elements III, I26, and I29 in engagement with the two cylindrical surfaces defining the side walls of the packing chamber I09. Adjacent the spacer M0 and the spacer IZ'I grease passages I35 and I33, respectively, are provided in the stumng box housing III. Suitable grease nipples, such as Alemite fixtures I3? and I30, are screwed into the passages I35 and I30 so that grease may be introduced but will be prevented from leaking from the stuffing box. It will be seen that the passages I35 and I30 communicate with grease pockets I00 and III provided by the spacers M0 and I27. When grease is introduced into the upper grease pocket III the pocket is first filled and thereafter grease will flow upwardly around and between the packing elements I29. The pressure, however, of the grease tends to force the packing elements I26 outwardly so that grease will not flow in a downward direction. When grease is forced into the lower pocket M0 the pocket is first filled and thereafter the grease is forced upwardly around the packing elements I26. It will be seen, therefore, that all of the space within the packing chamber I09 with the exception of that occupied by the various elements which have been described is filled with grease or other suitable lubricant which may be desired. The spring I32 holds the parts in proper operating position and performs its function until the rotary swivel is put into operation. When the slush pump 2I, as shown in Fig. l, is set into operation pressure is developed in the gooseneck 90 and the wash pipe 65. R0- tary mud under pressure may flow through a small passage I95 into the upper end of the packing chamber I 09 and press against the follower I39. It will therefore be seen that as the pressure of the rotary mud increases the force expanding the packing elements also increases. This increase in force is in direct proportion to the pressure of the rotary mud, and therefore when higher sealing characteristics are required they are automatically obtained. The pressure of the rotary mud may range between 1000 and 20,000 pounds.

As stated heretofore, the stufiing box body is provided with heat radiating fins, and therefore the temperature within the stuifing box will be maintained at a minimum. The packing may be replenished with grease at any time desired either during the operation of the rotary swivel or while it is out of service. This is possible due to the fact that the grease nipples I31 and I38 are mounted on a stationary part. The packing per se of the preferred form of our invention has been extensively used in the field and has proven to be highly satisfactory and of much longer life than those of the prior art. Even though wear occurs in the packing elements III, I26, and I29, a seal is still maintained. This is due to the fact that the wear occurs at the faces II4 which engage the rotating wash pipe 85, and as this wear occurs the walls III swing downwardly and outwear. The parts will not become misplaced even though there is no rotary mud pressure due to the presence of the compression spring I32. The packing may be conveniently replaced by loosening the nuts H35, removing the gooseneck 90, and then removing the packing assembly. It is unnecessary to disturb any other parts of the de vice. If desired, the grease nipples I31 and I38 may be removed and the stuffing box housing lifted upwardly through the opening 95. In this way the packing parts may be very easily removed and replaced. At this time free access is had to the wash pipe and the wash pipe may be disconnected from the spindle 4 3 by removing the nuts from the studs 88 and lifted upwardly through the opening 95.

In the alternative form of packing all parts are of the same construction and the same numerals are applied except as follows. The lower end of the stufling box housing 9? is opened and is provided with internal threads E56 to receive a threaded gland l5! which is screwed upwardly around the wash pipe 85. Packing rings- I53 are placed in the upper part of the packing chamber W9 and a lantern. i5 3 is placed in the packing chamber below the rings of packing 553. This lantern provides a grease pocket 555 to which grease is supplied through a passage i536 formed in the stufling box housing 9?, there being a grease nipple I51 threaded into the passage 8%. Placed below the lantern i5 5 are packing rings l5 which are engaged by the upper end of the gland I55. By screwing upwardly on the gland i at the packing is compressed and the gland may be locked in a desired position by means of a lock nut Hit. In this form of our invention the pressure is not automatically applied to the packing but must be manually applied by first loosening the lock nut 56 and thereafter screwing the gland Hit in an upward direction. This type of construction, however, has the other advantages of the general stufling box arrangement.

We claim as our invention:

1. In a swivel of the class described, the combination of a body comprising upper and lower separable parts; a spindle extending axially through said body and rotatably supported exclusively by said lower part; lower spacing bearings carried by said spindle and engaging said upper part, said spindle and said bearing means being removable downwardly from said upper part when said upper and lower parts are separated; and an upper bearing carried by said upper part and engaging said spindle, said upper bearing being removable upwardly from said upper part.

2. In a swivel of the class described, the combination of: a body comprising upper and lower separable parts; a spindle extending axially through said body and rotatably supported exclusively by said lower part; a hold-down bearing carried by-said spindle and engaging a lower face of said upper part; a lower radial bearing carried by said spindle and engaging said upper part; and an upper radial bearing carried by said upper part and engaging said spindle, said spindle, said hold-down bearing, and said lower radial bearing being removable downwardly from said upper part when said parts are separated. and said upper radial bearing being removable upwardly from said upper part.

3. In a swivel of the class described, the combination of a two part body comprising upper and lower separable parts; a spindle extending wardly, thus automatically compensating for the axially through said parts; a thrust bearing carried within said lower part; a flange portion on said'spindle and carried by said thrust bearing whereby said spindle is rotatably supported by said lower part; a hold-down bearing carried on said flange-portion and engaging a lower face of said upper part; a lower radial bearing carried by said spindle and engaging an inner annular wall of said upper part; and an upper radial bearing carried by said upper part and engaging said spindle, said spindle, said hold-down bearing and said lower radial bearing being removable downwardly from said upper part and said upper radial bearing being removable upwardly from said upper part.

4. In a swivel of the class described, the combination of a two part body comprising upper and lower separable parts, said lower part having walls forming an oil chamber; a thrust bearing within said chamber; a spindle-extending axially through said body and having a flange portion engaging said thrust bearing whereby said spindle is rotatably supported solely by said lower part; and walls forming sediment pockets in the lower wall of said chamber and positioned radially outward from said thrust bearing, said sediment pockets being accessible for cleaning when said parts are separated.

5. In a swivel of the class described, the combination of a two part body comprising upper and lower separable parts, said lower part having walls forming an oil chamber; a thrust bearing within said chamber; a spindle extending axially through said body and having a flange portion engaging said thrust bearing whereby said spindle is rotatably supported solely by said lower part; Walls forming sediment pockets in the lower wall of said chamber and positioned radially outward from said thrust bearing, said sediment pockets being accessible for cleaning when said parts are separated; and sealing means between said lower part and said spindle below said oil chamber.

6. In a swivel of the class described, the combination of: a spindle rotatably supported in a stationary body and projecting upwardly therefrom; a wash pipe carried on the upper end of said spindle and rotatable therewith; a bridge comprising a lower plate supported by said body and an upper ring spaced from said lower plate by a plurality of legs, said ring supporting a gooseneck for delivering fluid into said wash pipe; and a packing housing surrounding said wash pipe and having a flange confined between said ring and said gooseneck for the support thereof,

said packing housing extending downwardly from said upper ring and being exposed to the air for cooling.

'7. In a swivel. of the class described, the combination of a spindle rotatably supported in a stationary body and projecting upwardly therefrom; a wash pipe carried on the upper end of said spindle and rotatable therewith; a bridge comprising a lower plate supported by said body and including sealing means engaging said spindle to seal the space between said spindle and said body, and an upper ring spaced from said lower plate by a plurality of legs, said ring supporting a gooseneck for delivering fluid into said wash pipe; and a packing housing surrounding said wash pipe and having a flange confined between said ring and said gooseneck for the support thereof, said packing housing extending downwardly from said upper ring and being exposed to the air for cooling.

8. In a rotary swivel, the combination of: an

upper body section having an opening, a lower shoulder near the lower part thereof, and an upper shoulder near the upper end thereof; a lower body section adapted to be secured to said upper body section and providing a chamber; a rotatable spindle extending into said opening and said chamber; a thrust bearing in said chamber for taking the thrust of said spindle; and upper and lower radial bearings for said spindle and being respectively in engagement with said lower and upper shoulders.

9. In a rotary swivel, the combination of: an upper body section having an opening, a lower shoulder near the lower part thereof, and an upper shoulder near the upper end thereof; a lower body section adapted to be secured to said upper body section and providing a chamber; a rotatable spindle extending into said opening and said chamber; a thrust bearing in said chamber for taking the thrust of said spindle; upper and lower radial bearings for said spi-ndle and being respectively in engagement with said lower and upper shoulders; and a hold-downzibearihg for said spindle positioned between said thrust hearing and said radial bearings.

10. In a rotary swivel, the combination of: a body providing a chamber having an upper elongated small cross-sectional portion and a lower enlarged portion; a spindle extending into said chamber; a thrust bearing supported in said lower enlarged portion of said chamber for supporting said spindle; and a pair of spaced radial bearings for said spindle positioned in said upper small cross-sectional portion of said chamber.

11. In a rotary swivel, the combination of: a bodyproviding a chamber having an upper elongated small cross-sectional portion and a lower enlarged'portion; a spindle extending into said chamber; a thrust bearing supported in the lowermost part of said lower enlarged portion of said chamber for supporting said spindle; and

a pair of spaced radial bearings for said spindle positioned in said upper small cross-sectional portion of said chamber.

12. In a rotary swivel, the combination of: a

body providing a chamber having an upper elongated small cross-sectional portion and a lower enlarged portion; a spindle extending into said chamber; a thrust bearing supported in said lower enlarged portion of said chamber for supporting said spindle; a pair of spaced radial bearings for said spindle positioned in said upper small cross-sectional portion of said chamber;- and a hold-down bearing for said spindle positioned between said upper and lower portions of said chamber.

13. A combination ,as defined by claim 12 in which said spindle has a shoulder of larger crosssectional size than said upper portion of said chamber, and which is engaged; by said thrust and hold-down bearings.

14. In a swivel of the class described, the combination of: a spindle rotatablysupported in a' stationary body and projecting upwardly therefrom; a wash pipe carried on the upper end of said spindle and rotatable therewith; a bridge supported by said body and having a supporting wall spaced above said body; a gooseneck for delivering fluid into said wash pipe, supported by said supporting wall; and a packing housing surrounding said wash pipe and having a flange confined between said supporting wall and said gooseneck for the support thereof.

WILLIAM DAVIDSON. GUGLIELMO TREMOLADA.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3236266 *Feb 20, 1963Feb 22, 1966Fmc CorpMethod and apparatus for transferring fluid offshore
US4462617 *Aug 31, 1981Jul 31, 1984Terra Tek, Inc.High pressure rotary coupling
US7249632Mar 7, 2006Jul 31, 2007Mako Rentals, Inc.Top drive swivel apparatus and method
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US8146663Mar 29, 2011Apr 3, 2012Mako Rentals, Inc.Seal configuration for top drive swivel apparatus and method
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US8528631Oct 30, 2012Sep 10, 2013Mako Rentals, Inc.Seal configuration for top drive swivel apparatus and method
US8590611Jan 22, 2013Nov 26, 2013Mako Rentals, Inc.Combination swivel and ball dropper
US8726994Apr 2, 2013May 20, 2014Mako Rentals, Inc.Double swivel apparatus and method
US8776875Sep 10, 2013Jul 15, 2014Mako Rentals, Inc.Seal configuration for top drive swivel apparatus and method
US8893773Nov 21, 2013Nov 25, 2014Mako Rentals, Inc.Combination swivel and ball dropper
EP1540131A2 *Sep 9, 2003Jun 15, 2005Kip M. Robichaux"top drive swivel apparatus and method"
EP1870558A2 *Sep 9, 2003Dec 26, 2007Tomahawk Wellhead & Services, Inc.Top drive swivel apparatus and method
Classifications
U.S. Classification285/41, 285/94, 285/281, 285/61, 285/275
International ClassificationE21B21/02, E21B21/00
Cooperative ClassificationE21B21/02
European ClassificationE21B21/02