U.S. patent application number 11/936393 was filed with the patent office on 2009-05-07 for apparatus and method for gripping and/or handling tubulars.
This patent application is currently assigned to FRANK'S INTERNATIONAL, INC.. Invention is credited to Winfred Marvin Adkins, Jeremy R. Angelle, Jean Buytaert, Donald E. Mosing, Jon Andrew Veverica.
Application Number | 20090114398 11/936393 |
Document ID | / |
Family ID | 40351914 |
Filed Date | 2009-05-07 |
United States Patent
Application |
20090114398 |
Kind Code |
A1 |
Buytaert; Jean ; et
al. |
May 7, 2009 |
Apparatus and Method for Gripping and/or Handling Tubulars
Abstract
Gripping tool (10) and method to assemble tubular strings
comprising a shaft (51) having first and second externally and
oppositely threaded portions (52, 54)); and first and second
generally frusto-conical cams (32, 34) threadably received on the
first and second threaded portions. Cams (32, 34) adduct and abduct
upon rotation of the shaft (51) in the first and second directions,
respectively. Tool can comprise a plurality of jaws (42, 44)
disposed within the variable space intermediate the cams (32, 34).
Jaws (42, 44) cam radially outwardly upon adduction of cams (32,
34) to grip the wall of a tubular (90), and jaws (42, 44) can
retract radially inwardly upon abduction of the cams (32, 34) to
release. Tool (10) may comprise a shaft (101) having a bore (152)
to facilitate fluid flow into tubular (118), and may cooperate with
a fill-up and circulation tool and/or a cementing assembly.
Inventors: |
Buytaert; Jean; (Mineral
Wells, TX) ; Mosing; Donald E.; (Lafayette, LA)
; Veverica; Jon Andrew; (Katy, TX) ; Angelle;
Jeremy R.; (Lafayette, LA) ; Adkins; Winfred
Marvin; (Mineral Wells, TX) |
Correspondence
Address: |
STREETS & STEELE
13831 NORTHWEST FREEWAY, SUITE 355
HOUSTON
TX
77040
US
|
Assignee: |
FRANK'S INTERNATIONAL, INC.
Houston
TX
|
Family ID: |
40351914 |
Appl. No.: |
11/936393 |
Filed: |
November 7, 2007 |
Current U.S.
Class: |
166/380 ;
166/98 |
Current CPC
Class: |
E21B 19/07 20130101;
E21B 33/1291 20130101 |
Class at
Publication: |
166/380 ;
166/98 |
International
Class: |
E21B 31/20 20060101
E21B031/20 |
Claims
1. An internally gripping apparatus to releasably grip a tubular
member, comprising: a drive shaft having a first portion and a
second portion, each with external threads, the first portion
oppositely threaded from the second portion; a first camming body
and a second camming body, separated one from the other by a
variable jaw space, the first camming body threadably engaging the
first portion of the drive shaft and the second camming body
engaging the second threaded portion of the drive shaft, each
camming body having at least one sliding contact portion that is
positionable by rotation of the drive shaft within the camming
body; and a plurality of dual-tapered gripping jaws disposed at
least partially within the variable jaw space between the first
camming body and second camming body, each dual-tapered gripping
jaw having a tapered contact surface disposed in sliding engagement
with the contact surface of the first camming body and a second
contact surface in sliding engagement with the contact surface of
the second camming body; wherein axial rotation of the drive shaft
in a first direction simultaneously adducts the first camming body
and the second camming body, one toward the other, to slidably
displace the dual-tapered gripping jaws radially outwardly from the
variable jaw space therebetween and to a gripping position, and
wherein axial rotation of the drive shaft in the second, opposite
direction abducts the first camming body and second camming body,
one from the other, to increase the variable jaw space therebetween
to facilitate retraction of the dual-tapered gripping jaws radially
inwardly from a gripping position and toward the drive shaft.
2. A gripping assembly to internally grip a tubular member
comprising: a first axial cam and a second axial cam, in a variably
spaced-apart relationship, each having a bore to threadably engage
a camshaft, and together having opposed sliding contact surfaces
forming a variable jaw space there between; and a plurality of
gripping jaws, each received at least partially within the variable
jaw space, each gripping jaw having generally convergent sliding
contact surfaces, one to engage the second axial cam and one to
engage the first axial cam, and a radially outwardly disposed
gripping surface; wherein axial rotation of the camshaft adducts
the first cam and the second cam, one towards the other, to reduce
the variable jaw space and to slidably displace the gripping jaws
radially outwardly from the jaw space.
3. A tool to grip a tubular member comprising: a drive shaft having
a first threaded portion and a second threaded portion; a drive
motor operatively coupled to rotate the drive shaft; a first
camming body threadably received on the first threaded portion of
the drive shaft; a second camming body threadably received on the
second threaded portion of the drive shaft; and a plurality of
gripping jaws slidably deployed by adduction of the first camming
body and the second camming body toward a gripping position when
the drive motor rotates the drive shaft in a first direction.
4. The tool of claim 3, wherein the gripping jaws retract from the
gripping position when the drive motor rotates the drive shaft in
the second, opposite direction;
5. The tool of claim 3 wherein: the first camming body has an
exterior generally frusto-conical surface that diverges outwardly
from the drive shaft in a first longitudinal direction; and the
second camming body has an exterior generally frusto-conical
surface that diverges outwardly from the drive shaft in a second
longitudinal direction opposite the first longitudinal
direction.
6. The tool of claim 3 further comprising at least one guide member
rotatably securing the first camming body to the second camming
body such that the first camming body and the second camming body
are movable longitudinally one relative to the other, but the guide
member prevents the first camming body and the second camming body
from rotating one relative to the other.
7. The tool of claim 3 further comprising a motor coupled to rotate
the drive shaft.
8. The tool of claim 3 further comprising a pair of bail attachment
ears.
9. The tool of claim 3 wherein the drive shaft has a bore to
provide a fluid passageway extending longitudinally therethrough to
allow a fluid to be delivered into the bore of a tubular member
gripped by the tool.
10. The tool of claim 9 further comprising a valve coupled to the
bore of the drive shaft.
11. The tool of claim 9 wherein the tool includes a sealing element
to sealing against said interior wall of a tubular member gripped
by the tool.
12. The tool of claim 9 further comprising a nozzle coupled to the
bore of the drive shaft to extend the fluid passage.
13. An apparatus to grip a tubular member comprising: a gripping
assembly including a rotatable drive shaft having a first threaded
portion, a second threaded portion with the threads of the first
threaded portion pitched oppositely from the threads of the second
threaded portion, a fluid passageway extending longitudinally
through at least a portion of the drive shaft, at least one drive
motor to rotate the drive shaft, a first threaded camming body
threadably received on the first threaded portion of the drive
shaft, and a second threaded camming body threadably received on
the second threaded portion of the drive shaft, wherein the first
camming body and the second camming body are positionable along the
drive shaft by rotation of the drive shaft within the first camming
body and the second camming body to adduct the first camming body
and the second camming body one toward the other upon rotation of
the drive shaft in a first direction to reduce a variable annular
space therebetween and to thereby cam a plurality of gripping jaws
radially outwardly against the interior wall of a tubular member in
which the gripping assembly is inserted.
14. The apparatus of claim 13 further comprising: a pair of ears to
receive bail arms from which the apparatus is suspended.
15. The apparatus of claim 13 further comprising one or more
generally flat surfaces on the camming bodies to slidably engage
one or more generally flat surfaces on the gripping jaws.
16. The apparatus of claim 13 further comprising a seal disposed on
the exterior of the apparatus to seal with the interior wall of a
tubular segment.
17. The apparatus of claim 13 further comprising a valve in
communication with the fluid passageway, the valve having an open
position to permit fluid flow through the passageway and a closed
position to substantially prevent flow through the passageway.
18. A method of connecting a tubular segment to a tubular string
comprising the steps of: inserting a gripping tool into an end of a
tubular segment, said gripping tool comprising a drive shaft having
a first threaded portion and a second threaded portion, the second
threaded portion having threads that are pitched oppositely from
the threads of the first threaded portion, at least one drive motor
to rotate the drive shaft, a first camming body threadably received
on the first threaded portion of the drive shaft, a second camming
body threadably received on the second threaded portion of the
drive shaft, wherein the first camming body and the second camming
body are positionable along the first threaded portion and the
second threaded portion, respectively, of the drive shaft to adduct
one toward other when the drive shaft is rotated in a first
direction, and to abduct one from the other when the drive shaft is
rotated in the second, opposite direction, and a plurality of
gripping jaws cammed by said first camming body and said second
camming body when the drive shaft is rotated in the first direction
to deploy the gripping jaws radially outwardly from the drive
shaft; and operating the drive motor to rotate the drive shaft in
the first direction to engage the gripping jaws with the interior
wall of the tubular segment.
19. The apparatus of claim 18 further comprising the step of:
rotating the gripping tool using a top drive quill to make-up a
threaded connection between the tubular segment and a tubular
string.
20. The apparatus of claim 1 wherein the drive shaft comprises a
bore through the apparatus.
21. The gripping assembly of claim 2 wherein the drive shaft
comprises a bore through the apparatus.
22. The apparatus of claim 20 wherein the apparatus comprises an
external seal to seal with the interior wall of a tubular
segment.
23. The gripping assembly of claim 21 wherein the gripping assembly
is coupled to a seal to sealably engage with the interior wall of a
tubular segment to be gripped using the gripping assembly.
24. The gripping assembly of claim 2 wherein the camshaft has a
bore to permit fluid flow through the camshaft.
25. The gripping assembly of claim 24 further comprising a seal to
engage the interior wall of a tubular segment gripped by the
gripping assembly.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to an apparatus and method to
grip and/or handle tubular segments, such as tubulars used for
forming tubular strings that are used for lining earthen boreholes
drilled for oil and gas recovery. The present invention
specifically relates to a method and apparatus to assemble tubular
strings and/or install them in a borehole, and to disassemble
tubular strings.
BACKGROUND OF THE INVENTION
[0002] Tubular strings are critical components in the drilling and
completion of wells used for oil and gas recovery from mineral
deposits within geologic formations in the earth's crust. Tubular
joints, also called tubular segments, are generally joined together
using threaded connections to form tubular strings. Tubular strings
may be used to line an earthen borehole to prevent collapse of the
borehole and/or as a fluid conduit to produce fluid from a geologic
formation.
[0003] The assembly of a tubular string involves repetitive
handling of tubular segments. A tubular segment is secured to a
hoist and lifted above the earthen borehole containing the tubular
string. An add-on tubular segment is generally positioned over
well-center so that the externally-threaded pin end of the lower
end of the add-on tubular segment is received within the
internally-threaded box end of the previous tubular segment that
was added to the tubular string. A power tong may be used to grip
and rotate the add-on tubular segment to make up the threaded
connection comprising the pin and box ends of the abutting tubular
segments. For example, where the "box end up" method is used, when
the connection is made up and torqued to the appropriate tightness,
the tubular string may be released from the power tong and an
elevator may grip the box end of the newly added tubular segment to
suspend the tubular string within the borehole and unload a spider
that suspends the tubular string in the borehole. Once the spider
is disengaged, the elevator may be lowered to dispose the
lengthened tubular string deeper into the borehole until the box
end of the newly added tubular segment is positioned above the
spider for receiving the next add-on tubular segment to be made-up
into the tubular string. The newly added tubular segment is gripped
by a spider at or above the rig floor so that the box end
connection is presented just above the rig floor and ready to
receive and couple to a new add-on tubular joint. The elevator is
released from the tubular string and the next add-on tubular
segment is positioned for being threadably connected into the
tubular string. This cycle is repeated until the tubular string
achieves the desired length. The lifting, positioning, aligning
and/or rotating of a tubular segment to make-up the threaded
connection to a tubular string can be referred to as "handling" or
"manipulating" the tubular segment.
[0004] Various casing running tools have been proposed for use on
rigs equipped with top drive assemblies. Top drive assemblies
typically comprise rail-mounted motors powering a downwardly
disposed and rotatable drive shaft for rotating a pipe or a pipe
string. Casing running tools adapted for use with top drives are
typically connected to the powered drive shaft so that the top
drive can be used to rotate casing segments to make-up threaded
connections. A casing running tool for use with a top drive
assembly may comprise an internally gripping assembly receivable in
the presented end of a casing segment. Casing segments may be
lifted onto the rig floor using a single joint elevator or other
hoisting device, then the top drive assembly is typically used to
manipulate the casing running tool to couple the new segment to the
string in the borehole.
[0005] During the process of making up and running tubular
segments, fluid can be added to the bore of the tubular string to
prevent excessive differential pressure from damaging or collapsing
the tubular string. The addition of predetermined amounts of fluid
into the end of the tubular string accessible to the rig can
balance the hydrostatic pressure in the bore of the tubular string
with the hydrostatic pressure in the annulus between the tubular
string and the borehole wall or, if the borehole is cased, between
the tubular string and the casing.
[0006] There is a need for an apparatus for gripping and handling
tubular segments on a rig which can either be used with a top drive
or as a stand-alone tool on a conventional rig that is not equipped
with a top drive. The apparatus may be compatible for use with
fill-up and circulating tools, cementing heads, wiper plug
assemblies, and other devices for delivering and circulating mud
and other fluids, such as a cement slurry. A need exists for an
apparatus for joining tubular segments to a tubular string that
requires no external drive for powering and operating the tool.
There is a need for an apparatus for gripping a tubular segment
that will not loosen its grip on a tubular segment upon loss of
power to operate the gripping assembly of the apparatus. There is a
need for an apparatus that uses mechanical advantage to grip a
tubular segment with minimal mechanical power requirement compared
to conventional, asymmetrically deployed gripping devices. There is
a need for an apparatus for gripping a pipe segment that does not
cause excessive marking of the gripped surface of the pipe segment.
There is a need for an apparatus that uses sufficiently small
amount of mechanical power so that a portable energy source, such
as a battery, may be used to power the gripping assembly into and
out of gripping engagement with the tubular segment. There is a
need for an apparatus for gripping a tubular segment that is
adapted for use with a fill-up and circulation assembly for
introducing and circulating fluid in a borehole.
SUMMARY OF THE INVENTION
[0007] At least one embodiment of the present invention provides an
apparatus and method that satisfies some or all of the
aforementioned needs, and others. An embodiment of the apparatus
can internally grip a tubular segment for coupling the tubular
segment to a tubular string in a borehole. The apparatus can be
self-operable for gripping and releasing, and in one embodiment
does not require the apparatus be attached to, supported by or
driven by a top drive assembly. In addition to being suitable for
use with a top drive, an apparatus may be used as a stand alone
tool, e.g., an apparatus that may be suspended from the traveling
block of a conventional rotary rig. An apparatus may be used as a
single joint elevator and a method of the present invention may be
used for making up or running tubular strings into a borehole
and/or breaking out or removing tubular strings from a borehole, or
any combination thereof. An apparatus and method may be used with
conventional tools for introducing fluid into a tubular string and
for circulating fluid within a borehole. Moreover, an embodiment
can provide the consistent application of sufficient gripping force
to lift and/or threadably couple a tubular segment to a tubular
string without the use of hydraulic cylinders to power the gripping
jaws into engagement with the tubular segment being lifted and/or
coupled.
[0008] In one embodiment, there is provided an apparatus for
gripping and handling tubulars compromising a drive shaft, at least
one drive motor for rotating the drive shaft, a first camming body
threadably received on a first threaded portion of the drive shaft,
a second camming body threadably received on a second portion of
the drive shaft, and a plurality of gripping jaws slidably disposed
within a jaw space between the first and second camming bodies. The
gripping jaws are positioned about the drive shaft such that the
first and second camming bodies threadably adduct generally
longitudinally along the drive shaft one toward the other when the
drive shaft rotates in a first direction, and abduct generally
longitudinally along the drive shaft one away from the other when
the drive shaft rotates in the reverse direction.
[0009] The gripping jaws are slidably engaged by the first and
second camming bodies such that, when the drive shaft rotates in
the first direction, the first and the second camming bodies adduct
to slidably and evenly displace the gripping jaws from the jaw
space and radially outwardly away from the drive shaft to bear
against the interior wall of a tubular segment into which the
apparatus is received. The gripping jaws are radially outwardly
displaced to engage the internal wall of the tubular segment with
an amount of gripping force sufficient for lifting and coupling the
tubular segment to the tubular string. The adduction of the camming
bodies, one toward the other with generally synchronous movement,
provide an even application of force to the gripping jaws as they
engage and grip the interior wall of a tubular segment. This even
application of force across the gripping jaws may provide minimal
marking of the interior wall of the tubular.
[0010] In another aspect, the drive shaft of the gripping apparatus
may comprise an axially extending bore there through to allow
pressurized fluid to be delivered from the rig, through the bore of
the drive shaft, and into the bore of the tubular segment to be
gripped and rotated by the gripping apparatus. In another aspect,
the gripping apparatus may comprise a fill-up and circulation
assembly extending from the distal end of the drive shaft and into
the bore of the tubular segment gripped by the gripping
apparatus.
[0011] In another aspect, there is provided an apparatus for
handling tubulars comprising a gripping apparatus including a drive
shaft having an axial bore there through, a drive motor for
rotating the drive shaft, a first internally-threaded camming body
threadably received onto a first externally-threaded portion of the
drive shaft, and a second internally-threaded camming body
threadably received onto a second externally-threaded portion of
the drive shaft, such that the first and the second camming bodies
are threadably adducted along the drive shaft one toward the other
to narrow a jaw space when the drive shaft rotates in a first
direction and abducted one away from the other to widen the jaw
space when the drive shaft rotates in the reverse direction, and a
plurality of gripping jaws slidably engaged and displaced from the
jaw space radially outwardly away from the drive shaft by the first
and the second camming bodies when the drive shaft rotates in the
first direction and allowed to retract radially inwardly into the
jaw space toward the drive shaft when the drive shaft rotates in
the reverse direction.
[0012] The apparatus may further comprise an apparatus adapted for
being suspended from and supported by a pair of elongate bails. The
bails each have an upper and a lower connection, the upper
connection adapted for being coupled to the traveling block of a
conventional rig and the lower connection for coupling to the
gripping apparatus of the present invention. This embodiment may be
adapted for receiving at least a portion of a fill-up and
circulation assembly within the bore of the drive shaft.
Specifically, this alternate embodiment may be adapted for
receiving a hollow tubular member having an external elastomeric
seal within the bore of the externally-threaded drive shaft for
creating a seal between the discharge of a fluid pump on or near
the rig and the internal wall of the tubular segment gripped by the
gripping apparatus. The fill-up and circulation assembly may be
suspended from the traveling block and positioned between the
bails, and the fill-up and circulation assembly may be adapted for
being extendible and retractable for selectively inserting and
removing the lower end of the fill-up and circulation assembly from
the bore extending longitudinally through the rotatable drive shaft
of the gripping apparatus.
[0013] In another aspect, there is provided a method of coupling
tubular segments to form a tubular string and running the tubular
string into a borehole. The method comprises the step of inserting
a gripping apparatus into an end of a tubular segment, the gripping
apparatus comprising a drive shaft, a drive motor for rotating the
drive shaft, a first internally-threaded camming body threadably
received on a first externally-threaded portion of the drive shaft,
and a second internally-threaded camming body threadably received
on a second externally-threaded portion of the drive shaft, such
that the first and the second camming bodies adduct axially along
the drive shaft, one toward the other, to narrow a jaw space
intermediate the first and second camming bodies when the drive
shaft rotates in a first direction, and to axially abduct, one away
from the other, to widen the jaw space when the drive shaft rotates
in the second, opposite direction, and a plurality of gripping jaws
slidably engaged by the first and the second camming bodies such
that the first and the second camming bodies adduct to slidably cam
the gripping jaws from the jaw space radially outward away from the
drive shaft when the drive shaft rotates in the first direction,
and the first and second camming bodies abduct to accommodate
retraction of the gripping jaws into the jaw space when the drive
shaft rotates in the second, opposite direction.
[0014] The method of the present invention comprises the steps of
operating the drive motor of the gripping apparatus to rotate the
drive shaft such that the first and the second camming bodies of
the gripping apparatus adduct to deploy the gripping jaws into
gripping contact with an interior wall of the tubular segment, and
then the step of operating a hoist coupled to the gripping
apparatus to lift and position the gripping apparatus and the
tubular segment. Alternately, the method of the present invention
may comprise the steps of operating the drive motor of the gripping
apparatus to rotate the drive shaft such that the first and second
camming bodies of the gripping apparatus adduct to deploy the
gripping jaws into gripping contact with an interior wall of the
tubular segment, and then the step of operating a top drive or
other torquing tool to rotate the gripping apparatus and the
tubular segment to make-up a threaded tubular connection.
[0015] Further aspects, features, and advantages of the present
invention will be apparent to those of ordinary skill in the art
upon examining the accompanying drawings and upon reading the
following disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is an elevation partial cross-section view of one
embodiment of the gripping apparatus of the present invention in
the retracted position and received within the bore of a tubular
segment.
[0017] FIG. 2 is an elevation partial cross-section view of the
embodiment of the gripping apparatus of FIG. 1 deployed to the
gripping position.
[0018] FIG. 3 is an elevation partial cross-section view of an
alternate embodiment of the gripping assembly of the present
invention having a hollow drive shaft for receiving and cooperating
with a fill-up and circulation assembly, the gripping assembly
adapted for being supported by a pair of bails.
[0019] FIG. 4 is an elevation partial cross-section view of the
gripping apparatus of FIG. 3 received within the bore of a tubular
segment and aligned with a fill-up and circulation assembly,
wherein the fill-up and circulation assembly is in a disengaged
position aligned with the hollow bore of the drive shaft.
[0020] FIG. 5 is an elevation view of the gripping apparatus of
FIG. 4 with the fill-up and circulation assembly inserted within
the hollow bore of the drive shaft to facilitate the introduction
of pressurized fluid into the bore of the tubular string.
[0021] FIG. 6 is an elevation partial cross-section view of an
alternate gripping apparatus of the present invention comprising an
integral gripping apparatus and fill-up and circulation assembly
adapted for coupling to and being supported by pair of bails.
[0022] FIG. 6A is an enlarged elevation view of the camming bodies
of FIG. 6 illustrating generally flat surfaces machined into the
camming bodies for providing improved camming engagement between
each of the camming bodies and the gripping jaw.
[0023] FIG. 6B is an interior elevation view of one embodiment of a
gripping jaw having generally flat surfaces for mating engagement
with the flat surfaces on the opposed camming bodies of FIG.
6A.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
[0024] wn in partial FIGS. 1 and 2 are elevation partial
cross-section views of one embodiment of the gripping apparatus 10
of the present invention with portions of the gripping apparatus 10
and the tubular segment 90 shol cross-section. The drive shaft 51
is not shown in cross-section in FIGS. 1 and 2 to illustrate the
two externally-threaded portions of the drive shaft 51.
[0025] As shown in FIGS. 1 and 2, the gripping apparatus 10 of the
illustrated embodiment comprises a proximal end 11 and a distal end
19. The gripping apparatus further comprises, at the proximal end
11, a coupling 14 secured to a housing 22, and a motor 20 and a
battery 21 disposed within the housing 22. The gripping apparatus
10 further comprises, at the distal end 19, a nose guide 16, e.g.,
tapered bullnose, for guiding the gripping apparatus 10 into the
bore 92 of tubular segment 90. The embodiment of the gripping
apparatus 10 shown in FIGS. 1 and 2 further comprises two generally
axial cam guides 60, 62 extending between the housing 22 at the
proximal end 11 and the distal end 19.
[0026] The coupling 14 on the embodiment shown in FIGS. 1 and 2 is
a threaded and tapered coupling that may be used to couple the
gripping apparatus 10 to a sub 12 or other member. The sub 12 may
be coupled to a top drive assembly (not shown) for supporting and
rotating the gripping apparatus 10 as is known in the art.
Additionally or alternatively, the housing 22 may include other
attachment member(s), for example, as illustrated in FIGS. 3-6, as
a pair of laterally opposed lift ears 130 for suspending the
gripping apparatus 10 from a pair of elongate bails 132, 134
adapted for being hung from a traveling block.
[0027] The gripping apparatus 10 of the present invention may be
supported using a thread compensation assembly so that torque and
rotation may be applied to the gripping apparatus 10 while
accommodating movement of the gripped tubular in a direction
generally along the axis of the drive shaft 51. A splined load
compensation assembly, for example, utilizing an expandable
bladder, cylinders or the like, may compensate for overlapping of
threads during the make-up of a threaded connection by permitting
extension of the overall length of the thread compensation assembly
between the top drive assembly or traveling block and the gripping
apparatus. For example, a splined assembly attached to and
supporting the sub 12 in FIG. 2 can allow downwardly vertical
movement of the gripping apparatus 10 and the internally gripped
tubular segment 90 during threaded make-up of the connection
between the tubular segment 90 and a tubing string (not shown)
there below.
[0028] The gripping apparatus 10 illustrated in FIGS. 1 and 2
further comprises a motor 20 and battery 21 disposed within housing
22, a drive shaft 51 coupled to and extending downwardly from the
motor through an opening 50 in the portion of the housing 22
disposed toward the distal end 19 of the gripping apparatus 10. The
distal end 19 of the gripping apparatus 10 comprises an axle well
56 for rotatably receiving the distal end 59 of drive shaft 51
which can provide stability during powered rotation of the drive
shaft 51. The drive shaft 51 can be rotatable by operation of the
motor 20, and can include a first externally-threaded portion 52 of
the drive shaft 51 near its proximal end 50 and a second
externally-threaded portion 54 of the drive shaft 51 at a position
adjacent to the first externally-threaded portion 52. The gripping
apparatus 10 shown in FIGS. 1 and 2 further comprises a first
internally-threaded camming body 32 threadably received onto the
first externally-threaded portion 52 of drive shaft 51 and a second
internally-threaded camming body 34 threadably received onto the
second externally-threaded portion 54 of the drive shaft 51. Each
of the first and second internally-threaded camming bodies 32, 34
may comprise sliding inserts 32A, 34A, 42A, 44A disposed at a cam
angle to the axis of the drive shaft 51 onto which each of the
camming bodies 32, 34 is threadably received. The thickness of the
sliding inserts 32A, 34A, 42A, 44A may vary to adapt the gripping
apparatus 10 to grip varying diameters of tubular segments 90.
[0029] The sliding inserts on the camming bodies 32, 34 may
comprise a lubricious material adapted for low-friction sliding
contact, or the inserts may include one or more channels, grooves,
holes, slots or apertures (not shown) for dispensing, directing
and/or retaining a lubricant to the sliding surface. The camming
bodies 32, 34 may comprise generally frusto-conical portions
providing sliding surfaces for engaging and displacing gripping
jaws 42 and 44. Alternately, the camming bodies may comprise a
camming body having a cam surface and held in place on the shaft,
or positioned along the shaft, by a threaded member, such as a
threaded nut. The sliding surfaces can be sloped at a cam angle of
between about 0 degrees to about 90 degrees off parallel from the
axis of the drive shaft 51, e.g., between about 5 and about 45
degrees off parallel from the axis of the drive shaft 51, e.g.,
between about 10 and about 35 degrees off parallel from the axis of
the drive shaft 51 or between about 15 and about 25 degrees off
parallel from the axis of the drive shaft 51. The sliding surfaces
of the camming bodies 32, 34 can together form an annular jaw space
of variable size intermediate the camming bodies 32, 34, and
generally circumferentially around the drive shaft 51, for
selectively positioning a plurality of gripping jaws 42 and 44 as
described in more detail below. As will be discussed later in
relation to FIGS. 6A and 6B, the sliding surfaces of the camming
bodies 32, 34 may comprise one or more generally flat areas thereon
for engaging generally flat areas on the gripping jaws 42 and 44.
The flat areas promote greater camming surface area over the range
of adduction and abduction of the camming bodies that would be
unachievable with purely frusto-conical bodies.
[0030] The camming bodies 32, 34 may be generally restrained from
rotation with the drive shaft 51 to ensure desired adduction or
abduction to displace or retract, respectively, the gripping jaws
42 and 44. The first and second internally-threaded camming bodies
32, 34 may be mechanically restrained from rotation with the drive
shaft 51 so that the threaded engagement between the first
internally-threaded camming body 32 and the first externally
threaded portion 52, and the threaded engagement between the second
internally-threaded camming body 34 and the second
externally-threaded portion 54, results in rotation of the drive
shaft 51 relative to the camming bodies 32, 34 thereby producing
synchronous axial movement (adduction or abduction) of the camming
bodies 32, 34 along the axis of the drive shaft 51. Threads can be
any style and/or pitch, as is known in the art.
[0031] In the illustrated embodiment, the direction of the mating
threads on the first externally-threaded portion 52 and the first
internally-threaded camming body 32 are reversed from the direction
of the mating threads on the second externally-threaded portion 54
and the second internally-threaded camming body 34. As a result,
axial rotation of the drive shaft 51 in a first direction results
in axial adduction of the first and second internally-threaded
camming bodies 32, 34, i.e., one toward the other along the drive
shaft 51, and axial rotation of the drive shaft 51 in the second,
opposite direction results in axial abduction of the first and
second camming bodies 32, 34, i.e., one away from the other along
the drive shaft 51.
[0032] The positions of the camming bodies 32, 34, one relative to
the other, determines the size of the jaw space there between, and
the radial position of the plurality of gripping jaws 42 and 44
that are movably received within the jaw space intermediate the
sliding surfaces of the camming bodies 32, 34. FIGS. 1 and 2 show
two gripping jaws 42 and 44, each having two sliding surfaces, one
disposed in sliding contact with a sliding surface of the first
internally-threaded camming body 32 and the other disposed in
contact with a sliding surface of the second internally-threaded
camming body 34.
[0033] FIG. 1 shows the camming bodies in an abducted position one
relative to the other to form a generally widened jaw space. In
this condition, the camming bodies 32, 34 are disposed sufficiently
far apart to allow for substantial disengagement of the gripping
jaws 42 and 44 from the internal wall of the tubular segment 90 by
radial inward retraction of the plurality of gripping jaws 42 and
44 into the jaw space and toward the drive shaft 51. In this
condition, the camming bodies 32, 34 are disposed apart to allow
for fullest radial inward retraction of the plurality of gripping
jaws into the jaw space toward the drive shaft 51. FIG. 2 shows the
gripping apparatus of FIG. 1 actuated to a deployed position. The
internally-threaded camming bodies 32, 34 are shown after being
adducted, one toward to the other, e.g., to reduce the size of the
jaw space intermediate the camming bodies 32, 34. FIG. 2 shows the
camming bodies 32, 34 after clockwise (looking from motor 20 down
drive shaft 51 toward the bullnose 56) axial rotation of the drive
shaft 51, the camming bodies 32, 34 adducted to a deployed position
to substantially reduce the size of the jaw space, and to slidably
displace the gripping jaws 42 and 44 radially outwardly to engage
and grip the interior wall of the tubular member 90.
[0034] The drive motor 14 that rotates the drive shaft 51 to adduct
and abduct the camming bodies 32, 34 of the gripping assembly 10
shown in FIGS. 1 and 2 may be an electrically-powered motor with
either an external electrical power source or an on-board battery
21 as shown in FIGS. 1 and 2. The motor for rotating the
drive-shaft 51 may alternately comprise a hydraulically-powered
motor, a pneumatically-powered motor or a mechanically-powered
(manual) motor.
[0035] The internal grip applied by the gripping assembly 10 of the
present invention results in a self-tightening grip; that is, the
transfer of the weight of the tubular segment 90 to the gripping
jaws 42 and 44 of the gripping assembly 10, or downward force
against the gripping assembly 10, causes at least one of the
gripping jaws 42 and 44 to be further cammed outwardly according to
the cam angle of the sliding contact between the lower sliding
surface of the gripping jaws 42 and 44 and the mating sliding
surface of the second internally-threaded camming body 34. Also,
the gripping assembly 10 of the present invention provides a
balanced application of deployment forces on the gripping jaws 42
and 44 so that substantially all of the torque output from the
motor that is not converted to friction along the sliding contact
surfaces is transferred radially outwardly as engaging force on the
gripping jaws 42 and 44 to grip the interior wall of the tubular
member 90.
[0036] In the embodiment of the gripping apparatus 10 shown in
FIGS. 1 and 2, the entire apparatus is sized and configured to
enable insertion of the entire gripping apparatus, including the
motor 20, battery 21 and the housing 22, into the bore 92 of the
tubular segment 90. However, the motor 20, battery 21 and the
housing 22 may be sized and configured to remain outside the bore
92 of the tubular member 90, but still in operative engagement with
the drive shaft 51 to rotate the drive shaft and thereby displace
the camming bodies 32, 34 and the gripping jaws 42 and 44 to engage
or release the internal wall of the tubular segment 90.
[0037] The camming bodies 32 and 34 may each further comprise one
or more elongate apertures extending through the body on a path
generally parallel to the axis of the drive shaft 51. Apertures in
each of the camming bodies 32 and 34 may receive cam guides 60 and
62, respectively, to rotatably secure the camming bodies one to the
other, and to prevent rotation of the camming bodies 32 and 34 with
the drive shaft 51 while slidably permitting each camming body to
be displaced along the guide rods in response to rotation of the
threaded drive shaft 51. Alternately, as is discussed below in
relation to FIGS. 6A and 6B, the mating flat areas on the camming
bodies 32 and 34 and the gripping jaws 42 and 44 described above
for increasing the camming surface area may also be used to
rotatably secure the gripping jaws and the drive shaft in position
relative to the camming bodies, and thereby eliminate the need for
guide rods or apertures to prevent unwanted rotation of the camming
bodies with the drive shaft.
[0038] Each gripping jaw 42 and 44 may have a treated, coated or
machined surface to provide positive gripping of the internal wall
of the tubular segment 90 with minimal inelastic deformation or
marking or include a gripping jaw insert 45, which can have a
treated, coated or machined surface to provide positive gripping of
the internal wall of the tubular segment 90 with minimal inelastic
deformation or marking.
[0039] A gripping apparatus 10 may also comprise a biasing member
(not shown) for biasing the gripping jaws 42 and 44 radially
inwardly toward the retracted and disengaged position when the
drive shaft 51 is counter-rotated for releasing the tubular segment
90. The biasing features may comprise spring(s) or other elastic
members that engage and bias each gripping jaw 42 and 44. For
example, but not by way of limitation, one or more elastic members,
each having a first end and a second end, such as elastic bands or
straps or a coil spring, may be secured at the first end to
gripping jaw 42 and at a second end to the other gripping jaw 44 to
bias the gripping jaws 42, 44 one toward the other. Elastic
deformation of the elastic member allows the gripping jaws to be
cammed radially outwardly one from the other by adduction of the
camming bodies 32, 34 to engage and grip the internal wall of the
tubular segment 90. Subsequently, abduction of the camming bodies
32, 34 one away from the other permits the elastic members to exert
a restoring force on the gripping jaws 42, 44 and to thereby
restore the gripping jaws 42, 44 to their original positions.
[0040] An alternate embodiment of a gripping apparatus 100 is
illustrated in FIGS. 3-5. FIG. 3 is an elevation partial
cross-section view of an alternate embodiment of the gripping
assembly 100 of the present invention having a hollow drive shaft
151 for sealably receiving a fill-up and circulation tool within
its bore 152. A gripping assembly 100 can be adapted for support by
a pair of bails 132, 134, e.g., bails suspended and extending
downwardly from a traveling block (not shown in FIG. 3) on a rig.
The alternate embodiment of the gripping apparatus 100 depicted
also comprises a hollow drive shaft 151 having a bore 152, two
externally-threaded and oppositely-threaded portions 101, 102, a
first and a second internally-threaded camming bodies 103, 104
threadably received on the first and second externally-threaded
portions of the drive shaft 151 for adducting and abducting
movement one relative to the other, depending on the direction of
rotation of the drive shaft 151, and a plurality of gripping jaws
110 deployable radially outwardly from the drive shaft 151 by
adduction of the camming bodies 103, 104. However, the embodiment
illustrated in FIGS. 3-5 comprises a circumferential motor that
powers the rotation of the drive shaft 151 by rotation of an
open-ended sleeve 153 that couples to and rotates the drive shaft
151 leaving unobstructed axial access to the axial bore 152 in the
hollow drive shaft 151. The bore 152 of the drive shaft 151 can be
adapted for sealably receiving and cooperating with a fill-up and
circulation assembly (see FIGS. 4 and 5) for providing pressurized
fluid to the bore 119 of the tubular segment 118 gripped by the
gripping apparatus 100.
[0041] The hollow drive shaft 151 can have an externally-splined
portion 49 for mating rotational engagement with an
internally-splined sleeve 48 that is the power output element for
the motor 112. This configuration can permit sliding engagement
between the externally-splined portion 49 on the drive shaft 151
and the internally-splined sleeve 48 of the motor 112. The splined
coupling formed by the externally-splined portion 49 of the drive
shaft 151 and the internally-splined sleeve 48 of the motor 112 may
provide for axial compensation, e.g., during make-up of threaded
connections between a tubular segment and a tubular string to which
the segment is joined. Rotation of the camming bodies 103, 104
relative to the drive shaft 151 may be prevented using cam guides
like those described above, or using flat camming surfaces like
those described below in relation to FIGS. 6A and 6B.
[0042] FIG. 4 is an elevation view of the gripping apparatus 100 of
FIG. 3 received within the bore 119 of a tubular segment 118. The
bore 152 of the gripping apparatus 100 depicted is generally
vertically aligned with a fill-up and circulation assembly 156,
e.g., wherein the fill-up and circulation assembly 156 is in a
disengaged position above the bore 152 of the drive shaft 151 of
the gripping assembly 100. The fill-up and circulation apparatus
156, in one embodiment, comprises an elongate body 142 having a
proximal end 157 pivotally coupled to a pivot arm 144 that is
sealably coupled to a source of pressurized fluid (not shown), a
distal end 155 coupled to a nozzle 154 for directing fluid flow
from the pivot arm 144 and the internal bore of the fill-up and
circulation apparatus 156 that extends through the body 142 of the
fill-up and circulation tool 156 from near the proximal end 157 to
the distal end 155 for delivering fluid introduced from the source
of pressurized fluid through the pivot arm 144. The fill-up and
circulation tool 156 can further comprise a circumferential
external elastomeric seal 146 disposed between the proximal end 157
and the distal end 155 of the fill-up and circulation assembly for
sealably engaging the interior wall 151A of the bore 152 of the
drive shaft 151.
[0043] FIG. 5 is an elevation view of the apparatus of FIG. 4 with
the fill-up and circulation assembly 156 lowered and sealably
received within the bore 152 of the drive shaft 151, e.g., to
enable pressurized fluid to be introduced through the fill-up and
circulation assembly 156 into the bore 152 of the drive shaft and
into the bore 119 of the tubing string 118 for circulating the
well. Fluid introduced through the pivot arm 144 of the fill-up and
assembly 156 can flow through the bore of the body 142, through the
nozzle 154 and into the bore 119 of the tubular segment 118 gripped
by the gripping apparatus 100. An elastomeric seal 146 can prevent
pressurized fluid introduced through the fill-up and circulation
assembly 156 from being discharged to the atmosphere and/or forces
the introduced fluid down the bore 119 of the tubular string
118.
[0044] FIG. 6 is an elevation cross-section view of another
embodiment of the gripping apparatus of the present invention
comprising an integral gripping apparatus and fill-up and
circulation assembly 200, e.g., adapted for coupling to and being
supported by a traveling block and a pair of bails (not shown).
Gripping apparatus 200 is similar to the gripping apparatus 100 of
FIGS. 3-5 except that the gripping apparatus 200 of FIG. 6
comprises an upper adapter 202 above the motor housing 204 for
pivotably coupling a fluid or cement delivery pivot arm 205
directly to the gripping tool 200. The embodiment shown in FIG. 6
also comprises a fill-up and circulation assembly 206 extending
downwardly from the bottom of the gripping assembly portion 201 and
receiving fluid from the hollow drive shaft 208, and an isolation
joint 210, such as a ball and socket joint, for supportably
coupling the fill-up and circulation assembly portion 203 to the
bottom of the gripping assembly portion 201, thus permitting the
fill-up and circulation assembly portion 201 to remain stationary
while the gripping tool 200 is operated for gripping or releasing
the interior wall 212 of the tubular segment 214.
[0045] The fill-up and circulation assembly portion 203 shown in
FIG. 6 is a tool of the type described above which comprises a
sealing element 216, a guide ring 218, fluid nozzle 220 and an
optional extension sub assembly 222 which may be used to extend the
fill-up and circulation assembly portion to a longer length.
[0046] If cementing operations are desired, the nozzle 220 disposed
may be replaced with a cement wiper plug assembly, e.g., as
described in U.S. Pat. No. 6,431,626. A wiper plug launcher
assembly, e.g., of the type described in that patent, may be
disposed to selectively receive a launching member, such as a ball
or a dart, into the bore of the drive shaft 208 of the gripping
apparatus 200 to selectively launch cement wiper plugs into the
bore of the tubular string 206 to manage placement of cement in the
borehole/casing annulus. Introduction of launching members may
require the replacement of the upper adapter 202 with a cementing
head or launching assembly, and/or replacing the fill-up and
circulation assembly 203 with, e.g., a wiper plug assembly which
may includes a pair of detachable cement wiper plugs. In such an
arrangement, a launching member, such as a ball or dart, may be
released from the cementing head to be received in a targeted
cement wiper plug to launch the targeted wiper plug to isolate the
fluid in the bore of the tubular string 203 ahead of the wiper plug
from the cement slurry being pumped in behind the wiper plug. As
the predetermined volume of cement slurry is being pumped into the
tubular string, the first-launched wiper plug can lead the volume
of cement slurry down the bore of the tubular string towards the
end. Once all of the predetermined volume of cement slurry is
pumped into the bore of the tubular string, a second launching
member can be introduced to launch the second cement wiper plug
into the bore of the tubular string, e.g., to isolate the trailing
end of the volume of cement slurry from the fluid used to displace
the trailing cement wiper plug and the cement slurry ahead of it
down the bore of the tubular string. This system may be used to
provide precise placement of uncontaminated cement slurry into the
annulus.
[0047] The combination gripping and fill-up and circulation
assemblies 200 of the present invention can include a passageway
extending through the drive shaft 208 for delivering mud, fluid or
cement into the tubular drive shaft 208, a drive motor 209 for
engaging drive shaft 208 for rotating the drive shaft 208, a stop
pad 226 on the bottom of the motor housing 204 for engaging the end
of the tubular 214 when the tool 200 is fully inserted, and a pair
of opposing ears 230 extending laterally from the housing 204 for
pivotably attaching the combination gripping and fill-up and
circulation assemblies 200 for being suspended from a pair of
bails, or any combination thereof. The bails can extend, for
example, from a conventional traveling block and hook assembly
which is preferably mounted on rails inside a rig mast or derrick
structure so as to accommodate any reactive torque applied by the
tool drive motor.
[0048] FIG. 6A is an enlarged elevation cross-section view of the
camming bodies 207 and 209 of FIG. 6 illustrating generally flat
surfaces machined into the generally opposed camming bodies for
providing improved camming engagement between each of the camming
bodies 207 and 209 and the gripping jaw 224. The flat surfaces
provide greater camming surface area that is maintained over a
greater range of motion as the camming bodies slide against the
gripping jaw. FIG. 6B is an interior elevation view of one
embodiment of a gripping jaw 224 having generally flat surfaces
225A, 225B, 226A and 226B for mating engagement with the flat
surfaces 215A, 215B, 216A and 216B on the opposed camming bodies of
FIG. 6A. It should be noted that not all of the flat surfaces on
any cam engage all of the flat surfaces on any gripping jaw.
[0049] An embodiment of the opposed camming bodies and one gripping
jaw for cooperating with and being deployed by adduction of the
camming bodies is illustrated in FIGS. 6A and 6B. As shown in FIG.
6A, two flat surfaces 215A (to the right) and 215B (to the left)
are disposed in a generally side-by-side arrangement on the first
camming body 207. Similarly, two flat surfaces 216A (right) and
216B (left) are disposed in a generally side-by-side arrangement on
the second camming body 209. The first camming body 207 and the
second camming body 209 each comprise other similar pairs of
side-by-side flat surfaces that cannot be seen in the cross-section
view of FIG. 6A. The flat surface 225A on the top, left interior
portion of the gripping jaw 224 shown in FIG. 6B may be positioned,
within an assembled internally gripping tool, such as the one
illustrated in FIG. 6, to slidably engage the flat surface 215A on
the right side of the exposed portion of the first camming body 207
in FIG. 6A. The flat surface 225B on the top, right interior
portion of the gripping jaw 224 shown in FIG. 6B may be positioned,
within an assembled internally gripping tool, such as the one
illustrated in FIG. 6, to slidably engage the flat surface 215B on
the left side of the exposed portion of the first camming body 207
in FIG. 6A. Similarly, flat surface 226A on the bottom, left
interior portion of the gripping jaw 224 shown in FIG. 6B may be
positioned, within an assembled internally gripping tool, such as
the one illustrated in FIG. 6, to slidably engage the flat surface
216A on the right side of the exposed portion of the second camming
body 209 in FIG. 6A. The flat surface 226B on the bottom, right
interior portion of the gripping jaw 224 shown in FIG. 6B may be
positioned, within an assembled internally gripping tool, such as
the one illustrated in FIG. 6, to slidably engage the flat surface
216B on the left side of the exposed portion of the second camming
body 209 in FIG. 6A.
[0050] The gripping tool of the present invention may also comprise
an externally gripping tool. An alternate embodiment comprises an
externally gripping apparatus having a first generally ring-shaped
camming body with a sloped interior cam surface and a second,
opposed generally ring-shaped camming body with an oppositely
sloped interior cam surface, and a plurality of angularly
distributed and radially inwardly deployable gripping jaws
intermediate the first and second camming bodies. The tubular
segment is receivable within a bore formed by the aligned camming
bodies and the gripping jaws intermediate the camming bodies. The
oppositely-sloped camming surfaces on the interior of the
ring-shaped camming bodies together form a variable jaw space there
between, and the jaw space is reduced upon adduction of the camming
bodies, one toward the other, to reduce the jaw space and to
slidably displace the gripping jaws radially inwardly to engage and
grip the external wall of a tubular segment received within the
bore. The tubular segment is releasable from the apparatus by
abducting the camming bodies, one away from the other, to increase
the size of the jaw space to accommodate the radially outwardly
retraction of the gripping jaws so that more of the gripping jaws
are received into the jaw space formed between the
oppositely-sloped interior surfaces of the camming bodies.
[0051] The adduction and abduction of the camming bodies may be
implemented in one embodiment by forming threads on the radially
outwardly exterior of the first camming body, and forming
oppositely-pitched threads on the radially outwardly exterior of
the second camming body, and then by disposing the camming bodies,
along with the gripping jaws intermediate the camming bodies,
within the bore of an internally threaded sleeve having a first
internally threaded portion for threadably receiving the first
camming body and a second internally and oppositely threaded
portion for threadably receiving the second camming body. In a
manner much like the drive shaft of the internally threaded
embodiment described above, rotation of the internally threaded
sleeve in a first direction, relative to the two opposing camming
bodies received therein, causes the first camming body to move
downwardly toward the second camming body and the jaw space, and
the second camming body to move upwardly toward the first camming
body and the jaw space, to reduce the jaw space and slidably cam
and deploy the gripping jaws radially inwardly to engage and grip
the external wall of the tubular segment received within the
bore.
[0052] In an alternate embodiment, the adduction and the abduction
of the camming bodies may be implemented using a plurality of
externally-threaded drive shafts that are received within
internally threaded and aligned apertures through the camming
bodies that are generally parallel to, but offset from, the bore.
For example, but not by way of limitation, the first camming body
may comprise three generally parallel apertures there through that
are generally parallel to an axis of the bore of the generally
ring-shaped camming body into which the tubular segment is
receivable. The apertures of the first camming body are alignable
with a similar set of apertures in the second, opposing generally
ring-shaped camming body when the two camming bodies are aligned
and positioned within the gripping apparatus for receiving a
tubular segment therein. Each of the generally parallel apertures
of the first camming body are threaded oppositely the threads in
the aligned aperture of the second, opposite camming body. An
externally threaded drive shaft is received within each pair of
aligned apertures so that simultaneous rotation of the three drive
shafts in a first direction within the three pairs of aligned
apertures results in adduction of the camming bodies, one toward
the other, and rotation of the three drive shafts in the second,
opposite direction causes the camming bodies to abduct, one away
from the other.
[0053] Thus, the present invention is well adapted to carry out the
objects and attain the ends and advantages mentioned above as well
as those inherent therein. While presently preferred embodiments
have been described for purposes of this disclosure, numerous
changes and modifications will be apparent to those of ordinary
skill in the art. Such changes and modifications are encompassed
within the spirit of this invention as defined by the appended
claims.
[0054] The terms "comprising," "including," and "having," as used
in the claims and specification herein, shall be considered as
indicating an open group that may include other elements not
specified. The terms "a," "an," and the singular forms of words
shall be taken to include the plural form of the same words, such
that the terms mean that one or more of something is provided. The
term "one" or "single" may be used to indicate that one and only
one of something is intended. Similarly, other specific integer
values, such as "two," may be used when a specific number of things
is intended. The terms "preferably," "preferred," "prefer,"
"optionally," "may," and similar terms are used to indicate that an
item, condition or step being referred to is an optional (not
required) feature of the invention.
* * * * *