Note: Descriptions are shown in the official language in which they were submitted.
CA 02510137 2005-06-17
OILFIELD PIPE-HANDLING APPARATUS
FIELD OF THE INVENTION
The present invention relates in general to apparatus for transporting
oilfield tubulars
between a tubular storage area and the floor of a drilling rig or service rig
during well drilling
or servicing operations.
BACKGROUND OF THE INVENTION
Drill pipe and production tubing for oil and gas wells are typically provided
in the form
of round steel pipe (commonly referred to as tubulars), typically in sections
(or "joints") about
30 feet in length, with threaded ends for connecting tubulars into a drill
string or a production
string, depending on the operation being conducted. The term "make-up" is
commonly used to
refer to the process of connecting tubulars to each other (i.e., "making up" a
threaded
connection), and the term "break-out" refers to the process of disconnecting
tubulars (i.e.,
"breaking out" a threaded connection). Well drilling and well servicing
involve both make-up
and break-out functions, for a variety of purposes well known in the field.
During make-up
operations, sections of drill pipe or production tubing must be transported
from a pipe storage
rack of some sort to the rig floor for connection to the string already in the
well bore. During
break-out operations, the pipe sections must be transported from the rig floor
to the pipe rack
after they have been disconnected from the string.
Apparatus for handling tubulars during such field operations typically feature
a hoisting
mechanism that receives a section of pipe from a pipe rack (typically
horizontal) positioned
close to the drilling rig or service rig (as the case may be). The hoisting
mechanism then lifts
one end of the pipe and moves it laterally toward and above the rig floor, so
that it can be
engaged by the rig hoist, which moves the pipe into position for connection to
the string of pipe
in the well bore. This procedure is reversed during break-out operations. As
each pipe section
is disconnected from the string, it is lifted by the rig hoist, and workers
manouever the lower
end of the pipe laterally toward the hoisting mechanism of the pipe-handling
apparatus. The rig
hoist lowers the pipe onto the hoisting mechanism of the pipe-handling
apparatus, which in turn
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moves the pipe laterally away from the rig, while at the same time restoring
the pipe to a
horizontal orientation, whereupon it is moved to a horizontal storage rack.
The prior art discloses numerous examples of apparatus for handling tubulars
and
transporting them to and from pipe storage facilities positioned near a
drilling rig or service rig.
Canadian Patent No. 2,224,638, issued to Handley et al. on February 24, 2004,
describes a
horizontal pipe storage rack with an elongate pipe cradle having a shallow V-
shaped trough for
cradling a tubular. With a tubular thus "loaded" on the apparatus, the far end
of the pipe cradle
(i.e., the end farthest from the rig floor) is moved laterally toward the rig,
and by virtue of one
of several alternative mechanical arrangements, this lateral movement has the
effect of
simultaneously raising the inward end of the pipe cradle, and thus the inward
end of the tubular,
above the rig floor level so that it can be readily engaged by pipe elevators
manipulated by rig
floor workers.
The reverse procedure is followed when breaking out a drill string or
production string.
The Handley apparatus also provides means for rotating the pipe cradle about
its longitudinal
axis when it is lying in the plane of the pipe rack, so that a tubular cradled
in the trough of the
pipe cradle after being pulled from the well bore will roll out of the trough
and into the rack by
gravity.
Additional examples of prior art pipe-handling apparatus are disclosed in the
following
references:
- U.S. Patent No. 2,631,741 (Tucker), issued March 17, 1950
U.S. Patent No. 2,656,052 (Tucker), issued October 20, 1953
- U.S. Patent No. 3,053,401 (Jinkins, Jr.), issued September 11, 1962
- U.S. Patent No. 3,559,821 (James), issued February 2, 1971
- U.S. Patent No. 3,706,347 (Brown), issued December 19, 1972
- U.S. Patent No. 3,780,883 (Brown), issued December 25, 1973
- U.S. Patent No. 3,792,783 (Brown), issued February 19, 1974
- U.S. Patent No. 4,347,028 (Dugan), issued August 31, 1982
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- U.S. Patent No. 2,631,741 (Tucker), issued June 29, 1950
- U.S. Patent No. 4, 386,883 (Hogan), issued June 7, 1983
- U.S. Patent No. 4,552,498 (Dysarz), issued November 12, 1985
- U.S. Patent No. 5,122,023 (Mochizuki), issued June 16, 1992
S - U.S. Patent No. 6,069,925 (Morgan et al.), issued June 27, 2000
- U.S. Patent No. 6,533,519 (Tolmon et al.), issued March 18, 2003
- U.S. Patent Application No. 10/279,453 (Eastcott), filed October 23, 2002
- Int. Application No. PCT/DE00/03903 (Borgeling), filed November 7, 2000
Although each of these examples of prior art pipe-handling apparatus may have
beneficial operational features, there remains a need for pipe-handling
apparatus that can
perform the required pipe-handling functions with increased efficiency as
compared with prior
art apparatus. In addition, there is a need for apparatus that can perform
these functions while
having less mechanical complexity that the prior art apparatus. The present
invention is
directed to these needs.
BRIEF SUMMARY OF THE INVENTION
In general terms, the present invention is an oilfield pipe-handling apparatus
for use in
association with a pipe storage rack positioned adjacent to a drilling rig or
service rig. The
apparatus has an elongate pipe cradle with a trough for receiving and
supporting a section of
pipe, such as drill pipe or production tubing. In the preferred embodiment,
the trough is
V-shaped, and this configuration is conveniently achieved by fashioning the
cradle from two
steel plates or from a standard structural steel angle section. Alternatively,
the cradle may be
fashioned with a trough that is convexly curvilinear in cross-section.
The apparatus includes an elongate base structure with a horizontal base track
having an
inward end and an outward end. Preferably, the base structure is mounted on a
trailer chassis
for ease of transport. When the apparatus is being used in association with a
drilling rig or
service rig, it is positioned substantially perpendicular to the rig with the
inward end of the base
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structure adjacent to the rig and the outward end farthest from the rig. Also
included in the
apparatus is a track carriage that can freely move longitudinally along the
base track. The track
carnage may be slidable within the base track. In an alternative embodiment,
the track carriage
may have rolling means (such as wheels or rollers) such that the track
carriage moves in rolling
fashion along or inside the base track.
The outward end of the pipe cradle is mounted to the track carriage such that
it is
swivelable about a longitudinal swivel axis parallel to the cradle, while at
the same time being
rotatable, in a lengthwise sense, about a horizontal axis transverse to the
track. The purpose of
this bi-directionally rotatable mounting of the pipe cradle to the track
carriage will become
clear as the structure and operation of the apparatus are further explained
herein.
The apparatus also includes lift means disposed between the base structure and
the pipe
cradle. More specifically, the lift means is adapted to raise the inward end
of the pipe cradle
from a horizontal position to an elevated position, while also causing
longitudinally inward
displacement of the cradle. In one embodiment of the apparatus, this is
accomplished by
providing lift means in the form of a swing arm rotatably mounted at one end
(designated the
lower end) to the base structure near the inward end thereof, so as to be
rotatable about a
horizontal axis transverse to the base track. The other end (i.e., upper end)
of the swing arm is
mounted in bi-directionally rotatable fashion to the other end to the pipe
cradle. That is to say,
the swing arm is rotatable relative to the pipe cradle about a horizontal axis
parallel to the
rotational axis of the lower end of the swing arm, while the cradle is
swivelable relative to the
upper end of the swing arm about the aforesaid swivel axis.
The swing arm's point of connection to the cradle is located so as to lie
outward of the
connection to the base structure when the cradle is in the horizontal
position. When the swing
arm is rotated upward and toward the rig, the geometry of the swing arm
assembly raises the
inward end of the cradle while at the same time causing the track carriage,
and thus the outward
end of the cradle, to move inward toward the rig.
The swing arm may be provided in the form of a single member, or it may be in
the
form of a frame having multiple structural components, or in any other
suitable structural
configuration. The swing arm may be actuated by one or more hydraulic rams
mounted to the
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base structure and connected to the swing arm so as to create a third-class
lever configuration.
However, other suitable actuation means, including electrically-actuated and
pneumatically-
actuated mechanisms, will be readily apparent to persons skilled in the art of
the invention.
In the preferred embodiment, the swing arm is telescoping or otherwise
selectively
variable in length. This configuration facilitates adjustment of the height of
the inward end of
the pipe cradle when in the elevated position, so as to optimize rig floor
workers' access to the
cradle and to a pipe carried by the cradle. In the preferred embodiment,
extension or shortening
of the swing arm is effected by way of an additional hydraulic ram, but
persons skilled in the
art will appreciate that other effective means of adjusting swing arm length
may be devised
without departing from the principles of the present invention.
Also in the preferred embodiment, the invention incorporates features that
facilitate
loading pipe into the pipe cradle from a loading rack positioned adjacent to
one side of the
apparatus, and for offloading pipe from the cradle to an offload rack
positioned adjacent to the
other side of the apparatus. By virtue of the pipe cradle's bi-directionally
rotatable connections
to the swing arm and the track carriage, the pipe cradle is swivelable in
either direction about
the aforementioned swivel axis when the cradle is in a horizontal position
parallel to the base
structure. Accordingly, the preferred embodiment of the invention features
swivel means for
selectively orienting the pipe cradle in:
(a) a loading position, in which the pipe cradle is tilted toward the loading
rack such
that a pipe section from the loading rack can be readily moved into the trough
of
the cradle;
(b) a neutral position; and
(c) an offloading position, in which the pipe cradle is tilted toward the
offload rack
such that a pipe section held by the cradle will tend to roll out of the
trough by
gravity onto the offload rack.
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In the preferred embodiment, the swivel means comprises:
(a) a cradle sprocket mounted to and below the pipe cradle, said cradle
sprocket
having a circular gear section concentric with the swivel axis;
(b) a drive unit mounted below the pipe cradle, said drive unit having a
rotatable
drive shaft with an axis substantially parallel to the cradle;
(c) a drive sprocket mounted to the drive shaft; and
(d) a discontinuous drive chain disposed around the drive sprocket and
connected at
each end to the cradle sprocket such that rotation of the drive shaft will
cause the
pipe cradle to swivel about the swivel axis.
In the preferred embodiment, the drive unit is hydraulically actuated.
However, it will
be readily appreciated that the apparatus could alternatively use an
electrically-actuated or
pneumatically-actuated drive unit.
The swivel means preferably incorporates lock-out means to prevent the cradle
from
being moved into either the loading or offloading position except when the
cradle is in its
lowered, horizontal position. In embodiments where the drive unit is
hydraulically actuated,
the lock-out means may be provided by way of a valuing arrangement whereby the
pressure to
both sides of the motor is locked when the cradle is in the neutral position
and cannot be
released until a separate valve is opened to release the pressure to one side
or the other, so as to
allow the cradle to be pivoted to the loading position or the offloading
position. Suitable
valuing arrangements may be readily devised by persons skilled in the art of
the invention,
using well known technology and principles.
Suitable alternative swivel means may be readily devised by persons skilled in
the art
using known technology, without departing from the basic concept of the
present invention.
Also in the preferred embodiment, the invention includes cradle-loading means,
for
receiving a pipe section from the loading rack and loading it into the pipe
cradle. In one
embodiment, the cradle-loading means comprises two or more pipe-loading arms
oriented
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transversely and adjacent to the pipe cradle, with each pipe-loading arm
having an upwardly-
disposed notch adapted to receive a pipe section from the loading rack, such
that the pipe
section rests in and spans between the notches of the pipe-loading arms, with
the pipe section
adjacent to and substantially parallel to the pipe cradle. The pipe-loading
arms are operable
between a lower position in which a pipe section can roll by gravity from the
loading rack into
the notches of the pipe-loading arms, and a slightly raised, "pre-load"
position in which the
pipe section remains supported in the notches, with the outboard ends of the
pipe-loading arms
acting as stop members to prevent other pipe sections from rolling toward the
cradle.
The cradle-loading means also includes two or more kicker members, adapted to
displace a pipe section supported by the pipe-loading arms laterally toward
the pipe cradle.
The kicker members are operable between a stowed position, in which they
cannot interfere
with a pipe rolling off the loading rack into the notches of the pipe-loading
arms, and a
deployed position in which they push or otherwise urge the pipe section out of
the notches of
the pipe-loading arms and into the pipe cradle.
In the preferred embodiment, the kicker members are simple arms that rotate
about an
axis parallel to the pipe cradle. In an alternative embodiment, the kicker
members act in a
reciprocating or straight-line mode to push the pipe section into the cradle.
To load a pipe into the cradle from the loading rack, the pipe-loading arms
are initially
disposed in their lower positions and the kicker members in their stowed
positions, such that a
pipe section can roll into the notches of the pipe-loading arms by gravity.
The pipe-loading
arms are then moved to their raised positions, and then the kicker members are
actuated to push
the pipe out of the notches and into the trough of the cradle, which will have
been swivelled
into its loading position. The cradle is then swivelled to its neutral
position, whereupon the
swing arm may be actuated, thus raising the inward end of the cradle upward
and toward the rig
floor, thus positioning the inward end of the pipe such that it may be
conveniently manipulated
by rig floor workers for engagement with pipe elevators associated with the
rig. The rig hoist
then li$s the pipe, the outward (or lower) end of which slides upward along
the now-inclined
cradle until it is free of the cradle. The swing arm may be lowered any time
after the pipe has
been connected to the pipe elevators, thus returning the cradle to its
horizontal position adjacent
to the loading ramp, ready to load another pipe section.
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When a drill string or production string is being broken out, the procedure is
reversed.
The swing arm is raised so as to position the inward end of the cradle near
the rig floor.
Workers on the rig floor may then manipulate the lower end of a pipe section
suspended by the
rig hoist (after having been broken out of the string) into the elevated and
inclined pipe cradle.
The rig hoist then lowers the pipe, causing it to slide down along the cradle
until the inward (or
upper) end of the pipe can be disengaged from the pipe elevators and the pipe
rests securely in
the cradle. The swing arm is then lowered, thus returning the cradle to its
horizontal position,
whereupon the cradle may be swivelled to the offloading position such that the
pipe section
rolls out of the trough of the cradle and onto the offload rack.
In alternative embodiments, the cradle-loading means comprises two or more
loading
arms that adapted to receive a pipe from the loading rack (such as by being
provided with
notches as in the pipe-loading arms described previously), and operable
between a lower
position (for receiving a pipe from the loading rack) and a deployed preload
position in which
the loading arms urge the pipe into the pipe cradle. In other words, the
loading arms of this
alternative embodiment perform the functions of both the pipe-loading arms and
the kickers
described above. In this embodiment, separate stopper means of any suitable
construction will
be provided to prevent other pipe sections from rolling off the loading rack
toward the cradle
when the loading arms are being deployed to load the pipe into the cradle.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention will now be described with reference to the
accompanying figures, in which numerical references denote like parts, and in
which:
FIGURE 1 is an end view of the apparatus of the invention in accordance with
one embodiment, positioned adjacent to a drilling rig or service rig.
FIGURE 2 is a cross-section through the apparatus showing the pipe cradle in
the neutral position, lying in a horizontal position parallel to the base
structure.
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FIGURE 3 is a cross-section showing the cradle swivelled into the loading
position, with the pipe-loading arms in the lower position, ready to receive a
pipe from the loading rack.
FIGURE 4 is a cross-section showing the pipe-loading arms in the raised
position, with a pipe from the loading rack positioned in the notches of the
loading arms, with the ends of the pipe-loading arms restraining additional
pipes
on the loading rack.
FIGURE 5 is a cross-section showing the kicker members partially deployed
and in the process of lifting the pipe out of the pipe-loading arms and
directing it
toward the cradle.
FIGURE 6 is a cross-section showing the kicker members fully deployed and
positioning the pipe in the cradle.
FIGURE 7 is a cross-section showing the cradle swivelled back to the neutral
position, with the pipe loaded therein.
FIGURE 8 is a cross-section showing the loaded pipe cradle in the neutral
position, and the kicker arms returning to the stowed position.
FIGURE 9 is a cross-section showing the cradle swivelled into the offloading
position, with a pipe rolling out of the cradle onto the offload rack.
FIGURE 10 is a longitudinal section through the apparatus along Line A-A in
Fig. 1, showing the pipe cradle in the horizontal position, ready to lift a
pipe to
the floor of a drilling rig or service rig.
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FIGURE 11 is a longitudinal section showing the swing arm partially rotated so
as to move the inner end of the pipe arm toward the rig floor.
FIGURE 12 is a longitudinal section showing the swing arm extended and
rotated to vertical, with the inner end of the pipe arm above the rig floor.
S FIGURE 13 is a longitudinal section showing the swing arm partially
retracted
so as to lower the pipe arm, with the pipe in the cradle being connected to
the
pipe elevators of the rig.
FIGURE 14 is a longitudinal section showing the pipe cradle returned to the
horizontal position, with the rig hoist lifting the pipe out of the cradle.
FIGURE 15 is an elevational detail of the swivel means and upper swing arm
connection in accordance with one embodiment of the invention.
FIGURE 16 is a cross-section along Line B-B in Fig. 15, illustrating the pipe
cradle and upper swing arm connection in accordance with one embodiment.
FIGURE 17 is a cross-section along Line C-C in Fig. 15, illustrating the
sprocket and drive assembly of the pivot means in accordance with one
embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Figure 1 provides an end view of the apparatus of the invention, generally
indicated by
the reference numeral 10. In the Figures, the apparatus 10 is shown positioned
adjacent to a
drilling rig or service rig R having a rig floor RF, a hoist H, and pipe
elevators PE suspended
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from hoist H. The apparatus 10 includes a base structure 12 which in the
preferred
embodiment will be mounted on a trailer chassis 11 to facilitate
transportation of the apparatus
between well sites. The apparatus 10 is adapted for use in conjunction with a
loading rack 60
positioned along one side of the base structure 12 for storage of pipe
sections P to be installed
in a well, and an offload rack 62 for storage of pipe sections removed from a
well.
Loading rack 60 and offload rack 62 may be independent assemblies, but
preferably
they are hingeingly attached to base structure 12 by suitable hinge means 66,
such that the they
can be folded against the sides of the base structure 12 when not in use, such
as during
transport. Loading rack 60 and offload rack 62 will preferably be fitted with
manual or
hydraulic jacks 64 or other suitable height-adjustment means whereby the
loading rack 60 can
be sloped so that pipes P will roll down loading rack 60 by gravity toward
base structure 12,
and will roll down offload rack 62 by gravity away from base structure 12.
Offload rack 62
will be provided with suitable stop means 68 to prevent pipes P from rolling
off.
In Figures 1-9, apparatus 10 is shown with both the loading rack 60 and
offload rack 62
in position adjacent to base structure 12, but this is for illustrative
purposes only. When
running pipe into a well, it will only be necessary to use loading rack 60,
such that offload rack
62 is not needed and may be stowed (or folded up, in the preferred
embodiment). Similarly,
only offload rack 62 needs to be deployed when pulling pipe P out of a well
during tripping
operations.
As illustrated in the Figures, apparatus 10 includes an elongate pipe cradle
20 having a
trough 21 for receiving pipe sections that are to be run into a well or that
have been pulled from
a well. As shown in Figure 10, pipe cradle 20 has an outward end 20A (i.e.,
the end farthest
from rig R) and an inward end 20B. A pipe stop 22 of suitable construction
(e.g., a steel plate
or bracket) is disposed within trough 21 near outward end 20A of pipe cradle
20. As best seen
in Figures 10-14, pipe cradle 20 is connected at its outward end 20A to a
track carriage 16
adapted to move longitudinally along a base track 14 incorporated into base
structure 12. Track
carriage 16 and its connection to pipe cradle 20 are adapted such that outward
end 20A of pipe
cradle 20 can rotate about a substantially horizontal axis transverse to base
track 14 as track
carriage 16 moves along base track 14. In the embodiments shown in the
Figures, this is
achieved by provided track carnage 16 with rollers 18 that run within a base
track 14
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configured as a pair of spaced channel sections. However, it will be readily
apparent to persons
skilled in the field of the invention that this operational feature can be
provided by a variety of
other means. To provide only one example, track carriage 16 could have
rotatably-mounted
slide members that slide within channel sections in base track 14.
The connection of track carriage 16 to pipe cradle 20 is also adapted such
that pipe
cradle 20 can swivel about a swivel axis Xl parallel to pipe cradle 20. As
illustrated in Figures
10-14, apparatus 10 also has a swing arm 50 with its lower end 50A attached to
base structure
12 so as to be rotatable about a horizontal transverse axis X2 relative to
base structure 12.
Upper end 50B of swing arm 50 is connected to pipe cradle 20 by means of a bi-
directional
hinge assembly 70 which allows upper end 50B to rotate about a horizontal
transverse axis X3
passing through hinge assembly 70, while also allowing pipe cradle 20 to
swivel about swivel
axis Xl. An exemplary embodiment of hinge connection 70 is illustrated in
Figures 15 and 16,
which will be described in detail further on in this specification. Persons
skilled in the field of
the invention will appreciate that features of hinge connection 70 as
illustrated in Figures 15
and 16 can be readily adapted for incorporation into track carriage 16 to
enable pipe cradle 20
to provide similar bi-directional rotatability.
Swing arm 50 is provided with swing arm actuating means for rotating swing arm
50
about transverse axis X2. In the preferred embodiment, the swing arm actuating
means is
provided in the form of a hydraulic lift cylinder 54 pivotably connected at
one end to a fixed
point on base structure 12 and at the other end to a selected point along the
length of swing arm
50. As illustrated in Figures 10-14, li$ cylinder 54 is configured so as to
rotate swing arm 50
in the fashion of a third-class lever. However, other suitably effective
configurations of lift
cylinder 54, and other forms of swing actuating means, may be devised without
departing from
the principles of the present invention.
In the preferred embodiment, swing arm 50 has a telescoping or otherwise
extensible
and/or retractable auxiliary arm 52 whereby the overall length of swing arm 50
may be
adjusted. Auxiliary arm 52 is preferably provided in the form of an auxiliary
hydraulic
cylinder. Also in the preferred embodiment (and as conceptually indicated in
Figure 17), swing
arm 50 may be provided in the form of a frame having a pair of primary arms,
each having a
corresponding auxiliary arm 52. A suitable cross-member may be extended
between the
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primary arms for connection to a single lift cylinder 54; alternatively, a
lift cylinder 54 could be
provided for each primary arm.
Apparatus 10 also includes swivel means 30 for swiveling pipe cradle 20 about
a swivel
axis X1 generally parallel to pipe cradle 20. In the preferred embodiment
illustrated in Figures
S 15, 16, and 17, swivel means 30 comprises a cradle sprocket 32 which is
notched to receive
pipe cradle 20 as shown and which is rigidly fixed thereto such as by welding.
A drive unit 38,
such as a hydraulic motor, is supported on a motor bracket 72, which is
rigidly suspended from
a bushing support plate 76 by hanger plates 74 or other suitable means. A
cylindrical swivel
bushing 80 is mounted to the top of bushing support plate 76, and is disposed
between a pair of
spaced end plates 28 extending downward from pipe cradle 20. A swivel shaft 82
is
concentrically disposed within swivel bushing 80 and is rotatably mounted at
each end to the
end plates 28, such that the axis of swivel shaft 82 (which will also be
swivel axis Xl)
coincides with the rotational centerpoint of cradle sprocket 32. Drive unit 38
has a drive shaft
37 with a drive sprocket 36. A discontinuous drive chain 34 extends around
cradle sprocket 32
1 S and drive sprocket 36, and is fixed at each end to cradle sprocket 32
(such as by bolting or
welding).
A cylindrical pivot bushing 78 is mounted to the lower side of bushing support
plate 76,
transverse to swivel bushing 80 as shown in Figures 1 S and 16. A pivot shaft
79 (the centroidal
axis of which is transverse axis X3, previously mentioned) is rotatably
disposed within pivot
bushing 78 and rotatably connected at each end to a suitable bearing bracket
56 associated with
upper end SOB of swing arm 50 (as schematically indicated in broken lines in
Figure 16).
Because motor bracket 72 is rigidly suspended from and laterally restrained by
bushing support
plate 76, which by virtue of its pivoting connection to swing arm 50 cannot
rotate transversely,
motor bracket 72 cannot rotate transversely either. Motor bracket 72 thus
provides reaction
means for resisting torque resulting upon activation of drive unit 38, which
will therefore cause
drive chain 34 to rotate cradle sprocket 32 and swivel pipe cradle 20 about
swivel axis Xl.
In the preferred embodiment, pipe cradle 20 will be selectively swivelable
approximately 45 degrees either clockwise or counterclockwise (as shown in
broken lines in
Figure 17).
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As illustrated in Figure 17, pipe cradle 20 is preferably in the form of an
angle section,
but this is not essential; pipe cradle 20 may have other cross-sectional
configurations, as
previously mentioned. As shown in detail in Figure 17 (and generally in other
Figures), pipe
cradle 20 preferably has reinforcing plates 24 and 26 forming an elongate box
structure. This
or other forms of structural reinforcement may be desirable to increase the
flexural and
torsional strength and stiffness of pipe cradle 20. However, such
reinforcement is not essential
to the invention. For example, it may be feasible in some applications to
obtain the required or
desired structural properties by making pipe cradle 20 from a sufficiently
heavy steel angle.
Refernng now to Figures 2-9, apparatus 10 also includes cradle-loading means
comprising at least two pipe-loading arms 44 and two kicker members 42. The
loading arms
44 are spaced along the length of base structure 12, as are the kickers 42. In
the preferred
embodiment, each loading arm 44 is adjacent to a kicker 42, but this is not
essential; kickers 42
may be spaced apart from loading arms 44. Each loading arm 44 is hingeingly
connected to
base structure 12 on the loading rack side of base track 14, and has an
upwardly-oriented notch
46 near its outward end for receiving a pipe from loading rack 60. Loading
arms 44 are
operable between a lower position (best seen in Figure 3) in which a pipe can
freely roll off
loading rack 60 into notches 46, and a raised position (as shown in Figure 6,
for example) in
which loading arms 44 act as stoppers to prevent other pipe from rolling off
rack 60. In the
preferred embodiment, loading arms 44 are actuated by hydraulic cylinders 45
that move
loading arms 44 in the fashion of a third-class lever. However, other means of
actuation may
be used without departing from the present invention.
The purpose of kicker members 42 is to dislodge a pipe out of notches 46 of
loading
arms 44 so as to move it into pipe cradle 20, and skilled workers will
appreciate that kickers 42
may take various alternative forms to accomplish this purpose. In the
preferred embodiment,
however, each kicker 42 is an elongate arm that is hingeingly connected to
base structure 12 on
the loading rack side of base track 14. Kickers 42 are operable between a
stowed position (best
seen in Figure 4) in which they cannot interfere with the loading of pipe from
loading rack 60
onto loading arms 44), and a fully deployed position (as illustrated in Figure
6). Kickers 42 in
this embodiment may be actuated by hydraulic cylinders 43 in third-class lever
fashion as
shown in the Figures, but other actuation means are possible as well.
14
CA 02510137 2005-06-17
The operation of the apparatus 10 of the invention may now be readily
understood with
reference to the Figures. In Figures 2-9, pipe cradle 20 is lying in the
horizontal position along
base structure 12 (as also shown in Figure 10). In Figure 2, pipe cradle 20 is
in the neutral
position, with trough 21 oriented upward. Loading arms 44 are shown in the
raised position in
S Figure 2, such that they act as stoppers to prevent pipe sections P from
rolling down loading
rack 60. For illustrative purposes, kickers 42 are shown in a partly deployed
position. To load
a pipe section Pl from loading rack 60 using the apparatus 10, loading arms 44
are moved to
the lower position as in Figure 3, with kickers 42 (not shown in Figure 3) in
the stowed
position. Pipe Pl is thus free to roll by gravity into notches 46 of loading
arms 44. In
preparation for receiving pipe section P1, swivel means 30 is actuated so as
to swivel pipe
cradle 20 into the loading position as illustrated in Figure 3.
Referring to Figure 4, loading arms 44 are moved to the raised position, with
pipe Pl
supported in notches 46. Kickers 42 are then actuated to lift pipe Pl out of
notches 46 and
direct it toward pipe cradle 20. Figure 5 shows kickers 42 at a point where
they have been
raised slightly above horizontal so that pipe Pl has started to roll along
kickers 42 by gravity
toward pipe cradle 20. Figure 6 shows kickers 42 in the fully deployed
position, pushing pipe
Pl into trough 21 of pipe cradle 20. As shown in Figures 7 and 8, pipe cradle
20 is then
swiveled back to the neutral position, whereupon kickers 42 can begin moving
back toward the
stowed position.
Figures 10-14 illustrate how a pipe Pl, having been loaded in pipe cradle 20,
can then
be delivered to rig R using the apparatus 10 of the invention. Lift cylinder
54 is actuated to
rotate swing arm 50 about transverse axis X2, as shown in Figure 11. This
causes upper end
SOB of swing arm 50, by virtue of its rotatable connection to pipe cradle 20,
to raise the inward
end of pipe cradle ZO and draw it toward rig R, at the same time drawing track
carriage 16
toward rig R along base track 14.
In Figure 12, swing arm 50 has been rotated to the vertical position. Inward
end 20B of
pipe cradle 20 and pipe Pl are disposed at a point above rig floor RF. In
Figure 13, a worker is
shown connecting the inward end of pipe P1 to pipe elevators PE. Figure 13
also
schematically illustrates how the telescoping auxiliary arm 52 of the
preferred embodiment
may be used to adjust the height of pipe cradle 20 to facilitate connection of
pipe Pl to pipe
CA 02510137 2005-06-17
elevators PE. Hoist H of rig R may then be actuated, as shown in Figure 14, to
lift pipe P1 out
of pipe cradle 20 so that it can be added to the drill string or production
string being made up in
the operation. Lift cylinder 54 may then be actuated to rotate swing arm 50 so
as to restore
pipe cradle 20 to the horizontal position, whereupon the process is repeated
to load the next
pipe section from loading rack 60.
Further inward movement of the pipe relative to the structure 12 can be made
possible
by adapting swing arm 50 to rotate beyond the vertical position toward rig R.
Such additional
rotation will result in a lowering of the inward end of pipe cradle 20, but
this can be
compensated for as necessary by adjusting the length of auxiliary arm 52.
The apparatus 10 may also be used to handle pipe sections removed from a well
during
tripping operations, by carrying out the above-described steps in reverse
order. With pipe
cradle 20 in an elevated configuration similar to that shown in Figure 13, the
lower end of a
pipe Pl suspended from hoist H is positioned in trough 21 of pipe cradle 20
near its inner end
20B. Hoist H then lowers pipe Pl such that its lower end will slide down pipe
cradle 20 until it
rests in trough 21 of pipe cradle 20, generally as shown in Figure 13,
whereupon workers may
then disconnect pipe Pl from pipe elevators PE. Lift cylinder 54 is then be
actuated to rotate
swing arm 50 so as to restore pipe cradle 20 to the horizontal position,
generally as shown in
Figure 10. Next, swivel means 30 is actuated so as to swivel the pipe cradle
20 into the
offloading position as shown in Figure 9, such that pipe Pl may simply roll
out of pipe cradle
20 by gravity and onto offload rack 62. This procedure is then repeated for
the next pipe
section to be removed from the well.
It will be readily seen by those skilled in the art that various modifications
of the present
invention may be devised without departing from the essential concept of the
invention, and all
such modifications are intended to be included in the scope of the claims
appended hereto.
In this patent document, the word "comprising" is used in its non-limiting
sense to mean
that items following that word are included, but items not specifically
mentioned are not
excluded. A reference to an element by the indefinite article "a" does not
exclude the possibility
that more than one of the element is present, unless the context clearly
requires that there be
one and only one such element.
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