Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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STABILIZER FOR PIPE HANDLING EQUIPMENT
TECHNICAL FIELD
This invention pertains to an apparatus and method for handling pipe, and more
particularly, to an improvement in stabilizing various pipe handling equipment
with
respect to the bail(s) from which the equipment is suspended. This is
accomplished
with a stabilizing mechanism mounted to the pipe handling equipment, such as
an
elevator, which can suppress swinging and/or pivoting of the pipe handling
equipment
relative to the bail(s).
BRIEF DESCRIPTION OF DRAWINGS
Fig. 1A illustrates an unbalanced elevator.
Fig. 1 B illustrates an elevator prone to tipping.
Fig. 2A illustrates a slip type elevator with brackets mounted on the timing
ring.
Fig. 2B is a. top view of brackets mounted to an elevator timing ring, showing
the
bails in section.
Fig. 3 Illustrates a prior art method of stabilizing an elevator with chains.
Fig. 4A is an isometric view of an elevator and stabilizer mechanism in
accordance one embodiment of the invention.
Fig. 4B is a top view of the embodiment of Fig. 4A, showing the bails in cross
section.
Fig. 5A is an isometric view of an upright mounted to an elevator in
accordance
with a different embodiment of the invention.
Fig. 5B is an isometric view of an upright mounted to an elevator in
accordance
with one embodiment of the invention.
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Fig. 6 is an exploded view of a portion of the stabilizing mechanism in
accordance with one embodiment of the invention.
Fig. 7A is an isometric view of a stabilizer mechanism mounted to an upright
in
accordance with one embodiment of the invention.
Fig. 7B is an isometric view of a stabilizer mounted to an upright in
accordance
with another embodiment of the invention.
Fig. 8A is an isometric view of an elevator showing stabilizer mechanism
brackets attached directly to the elevator body in accordance with one
embodiment the
invention.
Fig. 8B is a top view of the embodiment of Fig. 8A, showing, the bails in
cross
section.
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
For a further understanding of the nature and objects of the invention,
reference
should be made to the following detailed description, taken in conjunction
with the
accompanying drawings.
A drilling rig operates to rotate a drill bit as the drill bit creates a
borehole. The
drill bit is connected to the drilling rig by sections of drill pipe,
sometimes referred to as a
pipe string. The drill pipe also provides drilling fluid to the drill bit. As
the borehole is
drilled deeper, additional pipe sections must be added to the pipe string.
Pipe handling
equipment, e.g., elevators, can hoist pipe sections off of pipe racks.into the
air so they
can be coupled together to form the pipe string. Elevators can also be used to
temporarily suspend entire pipe strings in the borehole. Elevators can also be
used to
manipulate casing and casing strings, in addition to drill pipe strings.
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Fig. 1A illustrates an unbalanced elevator 10 for stabbing a pipe string 12
disposed within a borehole (not pictured). Bails 14 (one ball is shown in Fig.
1A; a
similar bail is located on the opposite side of the unbalanced elevator 10)
typically
suspend elevators during their operation. The unbalanced elevator 10 includes
ears 16
(one ear is shown in Fig. 1A; a similar ear is located on the opposite side of
the
unbalanced elevator 10) for catching the loops of the bails. A pivot point is
created at
the point on each ear where the ear contacts the ball loop, resulting in a
pivot axis 18
(see Fig. 4A) about which the unbalanced elevator 10 freely pivots relative to
the bail.
Arrow 20 in Fig. 1A illustrates the direction of this pivot motion. The
unbalancing of the
elevator is created when the center of gravity 22 of the elevator is
misaligned with the
pivot point of the elevator ear and bail loop contact, or when there is a
misalignment
between the elevator axis 24 and the center axis 26 of the drill pipe 12.
Elevator stabilizers as described herein provide particular advantages for
unbalanced elevators. The unbalanced elevator 10 freely tips about this axis
18, and in
its resting position, the centerline 24 becomes misaligned with the axis 26 of
the pipe
string. Tilted misaligned elevators can cause difficulty grabbing pipe strings
12 because
the unbalanced elevator 10 may be tilted and will not readily slip over the
top of the pipe
string 12. The stabilizing systems and methods (i.e., stabilizers) of the
invention can
prevent this misalignment caused by unbalanced elevators, e.g., the
stabilizing system
and method can prevent the elevator from tilting relative to the bails.
The elevator stabilizers provide advantages when the weight of an elevator 30
is
distributed such that the elevator's center of gravity 22 is close to the
pivot axis 18 as
illustrated in Fig. 1B. For example, as the unstable elevator 30 is lowered
toward the
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pipe string 12, occasionally a lower guide 32 at the bottom of the elevator 30
contacts
the pipe string 12 causing the elevator 30 to tip or pivot at the pivot axis
18 as indicated
by path 20. The systems and methods of the invention stabilizes pipe-handling.
equipment relative to the bails, and therefore relative to the axis of the
pipe string by
preventing the pipe-handling equipment from pivoting about an essentially
horizontal
axis passing through the contact points of the elevator ears and bails.
Therefore, the
elevator is always maintained in a vertical orientation relative to the bails,
and therefore
relative to the pipe string with its central axis parallel to the axes of the
bails prevents
tipping caused in such unstable elevators because the stabilizers prevent the
elevator
from tilting relative to the center axis of the pipe string.
Figs. 2A and 2B illustrate an elevator 40 comprising a body 42 and a timing
ring
44 with a first bracket 46 and a second bracket 48 attached to the elevator
timing ring.
The timing ring 44 simultaneously actuates a number of slips (not shown) in a
slip-type
elevator 40 to engage/disengage a pipe section 12 (not shown). A set of
pneumatically
or hydraulically actuated pistons 47 operate to raise/lower the timing ring 44
vertically
relative to the elevator body 42. The timing ring 44 actuates the slips Into
different
positions depending on the location of the ring 44 relative to the body 42. In
this way
the timing ring 44 causes the slips to grip onto/release a pipe section within
the elevator.
Ears 50 and 52 attached to the elevator body 42 receive bail loops therein to
suspend
the elevator 40.
Fig. 2B illustrates the first bracket 46 and second bracket 48. These brackets
serve as limits to potential pivotal movement of the elevator. A first bail 54
and a
second bail 56 are shown in cross section in relation to the elevator 40.
These brackets
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are rigidly connected to the timing ring 44, which moves up and down relative
to the
elevator body, and therefore relative to the bails. In this configuration,
contact between
the bails and the brackets results in scraping and may damage the pistons by
cocking
the timing ring relative to the elevator body. Preventing this contact
requires significant
clearance between the bails and the brackets because bails produced to handle
differing loads or produced by different manufactures come in a variety of
diameters..
Additionally, irregularities on the surfaces of the bails extend the clearance
required and
increase the potential for damage should the brackets contact the bail while
moving.
Fig. 3 illustrates an elevator stabilizing system previously known in the art
with
the elevator 40 suspended from a first bail 54 at the attached ear 16.
Elevator 40 pivots
relative to the bail 54 in the direction indicated by arrow 20. A chain 58 is
wrapped
around the first bail 54 to limit the elevator's pivoting motion as indicated
by arrow 20.
In one such prior art device, the chain 58 is attached to the elevator 40,
then wrapped
around and below the elevator and attached to the bail 54. The tension in
chain 58
reduces the pivoting of the elevator 40.
Fig. 4A illustrates an elevator 40, which may be balanced or unbalanced as
well
as prone to tipping or not prone to tipping, employing an adjustable
stabilizing
mechanism of the invention. The adjustability of this embodiment allows for
the
stabilizing mechanism to be used on a variety of elevator designs and bail
designs. The
same adjustable stabilizing mechanism accommodates different sized bails as
well as
different ball configurations.
The elevator 40 includes a first ear 16 and a second ear (not shown) located
on
the opposite side of the elevator 40. A first bail 54 comprises a shaft 60 and
a loop
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defining a slot 62 therein for receiving the elevator ear 16. A second bail 56
receives
the ear on the opposite side of the elevator 40 in the same way, suspending
the
elevator from the first bail 54 and the second bail 56, creating a pivot axis
18 which
allows the elevator 40 to otherwise pivot relative to the bails, and therefore
relative to
the pipe string. Pipe string 12 is shown passing through the top flange of a
timing ring
44 and through the elevator 40.
In this embodiment, a first stabilizer system 64 adjustably contacts the first
bail
54 and a second stabilizer 66 adjustably contacts the second bail 56 to reduce
pivotal
movement of the elevator 40 about the pivot axis 18. The first stabilizer
system 64
comprises a first stabilizing mechanism 68 and a second stabilizing mechanism
70
attached at the end of a rigid member (e.g., first upright 72). Rigid member
72 can be
bolted, welded, or otherwise attached (e.g., rigidly attached) to the body of
the elevator
40 or to the timing ring 44. The top surface of the depicted timing ring 44 is
approximately the same size and configuration as top surface of the elevator
body 42.
Therefore, in order to attach the first upright 72 to the elevator 40, the
timing ring 44 is
formed with a cut out 74 to accommodate the first upright 72. This is best
shown in Fig.
4B.
Briefly referring to Fig. 7A, the first stabilizing mechanism 68 and second
stabilizing mechanism 70 attach to a seat 76, which is attached to the upright
72.
Returning to Fig. 4A, the spacing between the first stabilizing mechanism 68
and the
second stabilizing mechanism 70 accommodates the first bail 54. Adjusting the
adjustable contacting member 94 on the first stabilizing mechanism 68 and the
adjustable. contacting member 94 on the second stabilizing mechanism 70 urges
the
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adjustable contacting members into abutment with the baits to firmly grip the
bails
between them, preventing the elevator 40 from swinging or pivoting with
respect to the
bail in either direction. This is best shown in Fig. 4B.
Fig. 4A illustrates the elevator 40 suspended from the bail and secured by the
stabilizer mechanism. The first stabilizer 64 includes the first upright 72,
the first
stabilizing mechanism 68 and the second stabilizing mechanism 70. A second
stabilizer
66 secures the second bail 56. The second stabilizer 66 includes a third
stabilizing
mechanism 78 and a forth stabilizing mechanism 80 mounted to a second upright
81.
Fig. 4B is a top view of the embodiment of the invention illustrated in Fig.
4A.
Fig. 4B illustrates the adjustable contacting member 94 of the first
stabilizing
mechanism 68 and the adjustable contacting member 94 of the second stabilizing
mechanism 70 of the first stabilizer 64 adjusted into contact with first bail
54. The
adjustable contacting member 94 on the third stabilizing mechanism 78 and the
adjustable contacting member 94 on the forth stabilizing mechanism 80 on the
second
stabilizer 66 secure the second bail 56. Each stabilizing mechanism serves to
suppress
the pivoting motion of the elevator 40 relative to the bails.
In Fig. 4B, arrow 20 indicates the path along which the elevator 40 (which is
rigidly attached to first upright 72) would otherwise pivot relative to first
bail 54. Fig. 4B
illustrates the first stabilizing mechanism 68 suppressing the motion of the
elevator
because there is no clearance for movement in one direction. along path 20,
and the
second stabilizing mechanism 70 suppresses any clearance for the elevator 40
to move
the other direction along path 20. It can be seen in Fig. 4B that there is no
clearance for
the first bail 54 to move toward the first stabilizer 64 because the first
bail 54 rests
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against the first adjustable member 94 of the first rigid member 68 and the
adjustable
member of the second stabilizing mechanism 70. In this manner, motion in the
direction
labeled 82 is suppressed, This motion in directions 82 and 83, perpendicular
to motion
20, is suppressed because bails are located on opposite sides of the elevator.
In the
embodiment disclosed in Fig. 4A and Fig. 4B, each stabilizing mechanism is
adjustable
so they may be adjusted into abutment with the bails. One illustrative example
of the
adjustable mechanism will be described in greater detail below.
While the embodiment illustrated in Figs. 4A and 4B shows a stabilizer on each
bail with a total of four stabilizing mechanisms, an alternative embodiment
contemplates
three, two or even a single stabilizing mechanism. For example, in the case of
an
unbalanced elevator that naturally tends to misalignment in a single
direction, the weight
distribution of the elevator biases the elevator body to rotate in the same
direction
relative to the bails. In order to prevent this misalignment, one stabilizing
mechanism
can be placed on the "light side" of the elevator at one bail. In this way, a
single
stabilizing mechanism can be used to prevent the elevator body from rotating
in one
direction, and the forces tending to misalign the elevator body will act
against rotation in
the other direction.
Fig. 5A illustrates the bottom of the first upright 72 attached to the top of
the
elevator body 42. The top flange of the timing ring 44 is shown, as well as
the cut out
74 through. which the first upright 72 passes. A flat piece 84 attaches the
first upright 72
to the body of the elevator 42. The flat piece 84 contains holes 86 for
receiving bolts
(not shown) and connects to the first upright 72. Bolts are mated through
holes 86 and
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into corresponding holes in the body of the elevator 42. The first upright 72
may also be
welded at 88 to the elevator body 42, or bolted or both.
Fig. 5B illustrates another configuration for attaching an upright to a
portion of the
elevator body 42. The bottom portion of an upright 90 is illustrated in the
shape of a "C"
5. bracket or a channel with three sides and a bottom 84. In this
configuration, through
holes 86 in the flat piece inside the channel of the "C" bracket. This
configuration
utilizes less space, providing an advantage in smaller or more compact
elevators.
Upright 90 may be welded at 88 to the elevator body 42, or bolted or both.
Figs. 5A and
613 provide two illustrative examples for securing the upright to the body of
an, elevator
40. One of ordinary skill in the art would appreciate a number of equivalent
configurations for attaching an upright to a portion of the elevator body or
to a timing
ring, all of which are encompassed in the invention as defined by the claims
attached
hereto. The configurations described above attach the uprights to elevator
body 42, but
in certain embodiments the uprights could be fastened to the top flange of the
timing
ring 44 in the same manner described with respect to Figs. 5A or 5B.
Fig. 6 illustrates one embodiment of the adjustable contacting member 94 for
the
stabilizing mechanisms. The first stabilizing mechanism 68 comprises a rigid
member
92, an adjustable member 94, and an adjustment nut 96. In one embodiment, the
rigid
member 92 is a rod. The rigid member 92 comprises a first end 98, a second end
100,
and; a threaded portion 102. A back washer 104 slides onto the first end 98 of
the rigid
member 92 and is welded at 106 into place at a location for creating a limit
on the range
through which the mechanism can be adjusted The adjustment nut 96 then slides
on
the second end 100 of the rigid member 92 and mates to the threaded portion
102 of
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the rigid member 92. The back washer 104 prevents the adjustment nut 96 from
coming off the first end 98 of the rigid member 92. An adjustable member 94
with a
through hole 108 slides onto the second end 100 of the rigid member 92. The
adjustability of this embodiment permits the adjustable contacting member(s)
94 to be
urged into direct and firm contact with the bail in order to prevent or
minimize tipping or
pivoting of the elevator relative to the bail. The adjustable member 94 can be
in the
shape of a frustum cone, and the base of the cone is slid into contact with
the
adjustment nut 96. The conical shape is advantageous for securing the
adjustable
contact member 94 against bails of different sizes and configurations.
However, any
number of shapes could be employed for the adjustable member 94. In addition,
the
frustum cone could be slid onto the rigid member 92 in the reverse orientation
so the
small truncated portion contacts the adjustment nut 96 and the larger base of
the cone
contacts the bail. The adjustable member can be a hard rubber, plastic
material, a
resilient material, or any other material desired. Those skilled in the art
will also
appreciate that the adjustment nut 96 may be formed with the adjustable
contacting
member 94 so that rotating the adjustable contacting member adjusts it into
abutting
contact with the bail.
The conical shape of the adjustable contacting member 94, in combination with
the through hole 108, allows the adjustable contacting member 94 to rotate
about the
rigid member 92 when the rigid member is a rod. This rotation provides a
particular
advantage when the stabilizer 64 is attached to a part that moves up and down
relative
to the baits during operation.. For example, if the timing ring 44 moves up
and down
relative to the elevator body. Because the bails do not move, the stabilizer
64 attached
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to the timing ring 44 actually slides up and down the bails during operation.
Because
the adjustable member 94 is rubber, it can rotate about the rigid member 92,
significantly suppressing unwanted motion by maintaining the adjustable
contacting
member 94 in close contact with the bails with minimal damage and grinding to
the
parts. Finally, a washer 110 with an outer diameter greater than the through
hole 108 of
the adjustable member 94 is fixed to the second end 100 of the rigid member
92.
Washer 110 retains the adjustable member 94 and the adjustment nut 96 on the
rigid
member 92. Washer 110 can be welded to the second end 100 of the rigid member
92,
or attached in any other manner known in the art.
Referring to Figs. 4B and 6, the adjustable stabilizer operates as follows. A
set
of bails suspends the elevator 40. Adjustment nut 96 on the first stabilizing
mechanism
68 is adjusted to urge the adjustable contacting member 94 of the first
stabilizing
mechanism 68 along the stabilizing member 92. It should be pointed out that
the
adjustable contacting member 94 can slide along the stabilizing member 92, and
can
also threadedly engage the stabilizing member so that rotating the adjustable
contacting
member will urge the adjustable contacting member into abutment with the bail.
The
adjustable contacting member 94 of the second stabilizing mechanism 70 is
similarly
adjusted into contact with the bail in the same manner. Once the adjustable
contacting
member 94 of the first stabilizing mechanism 68 and the adjustable contacting
member
94 of the second stabilizing mechanism 70 have been urged into abutment with
the first
bail 54, the motion of the first bail 54 is suppressed with respect to the
elevator 40.
Referring back to Fig. 4B,. the adjustable contacting member 94 of the third
stabilizing
mechanism 78 and the adjustable contacting member 94 of the fourth stabilizing
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mechanism 80 of the second stabilizer 66 are then urged against the second
bail 56 in a
similar fashion, retaining the pipe handling equipment in proper alignment
relative to the
second bail 56.
Fig. 7A illustrates the first stabilizing mechanism 68 and the second
stabilizing
mechanism 70 mounted to the first upright 72 (the adjustable contacting
members and
adjustment nuts of the stabilizing mechanisms are not shown). The rigid member
92 of
the first stabilizing mechanism 68 and second rigid member 112 of the second
stabilizing mechanism 70 are each welded to a seat 76, which is attached to
the top
surface of the first upright 72. Seat 76 extends past the top surface of the
first upright
72, providing a greater surface area for welding each of the rigid members of
the
stabilizing mechanisms. By affixing the rigid members along the edges of the
seat, as
shown in Fig. 7A, they can be offset by predetermined angles corresponding to
the
shape of the seat 76. In one embodiment, the seat's 76 trapezoidal shape
directs each
rigid member to point slightly outward. With reference to the first
stabilizing mechanism
68, it can be seen that the rigid member 92 is welded to the seat 76 at the
first end 98 of
rigid member 92 along an edge of the seat 76. Threaded portion 102 extends
away
from the seat 76 for receiving the adjustment nut 96 and adjustable member 94.
The
second rigid member 112 of the second stabilizing mechanism 70 is similarly
welded
along another edge of the seat 76.
Fig. 7B illustrates an embodiment of the invention which can be attached
directly
to a stable portion of an elevator, as illustrated in Figs. 5A or 5B and
previously
discussed. A first rigid member 116 and a second rigid member 118 attach to a
first
upright 72. The first rigid member 116 and the second rigid member 118 may be
curved
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in shape or they may be straight. The embodiment depicted in Fig. 78 contains
a latch
120 configured with a first slot 122 and a second slot 124. The first slot 122
receives
the end of the first rigid member 116 and the second slot 124 receives the end
of the
second rigid member 118. Once a bail (not shown) has been disposed between the
first
rigid member 116 and the second rigid member 118, the latch 120 can be aligned
to
cover the lateral bail-insertion opening defined by the two stabilizing
members 116, 118.
Through holes 126 in the latch are matched to a pin hole 128 in the first
rigid member
116. Likewise, second though holes 130 are matched to a pin hole 132 in the
second
rigid member 118. Once these holes are aligned, a fastener 134 such as a pin
or bolt
with -a threaded end is placed through a washer 136 then through the through
holes 126
of the latch 120 and the pin hole 128 of the first rigid member 116. A nut 138
is secured
to the bolt 134 on the other side of the rigid member 116. A second bolt 140
is put
through a 'second washer 142 then through the through holes 130 of the latch
120 and
the pin hole 132 of the second rigid member 118. A nut 144 is secured to the
bolt 140
on the other side of the second rigid member 118. While Fig. 7B illustrates
curved rigid
members and a latch assembly, one embodiment contemplates a bracket or set of
straight rigid members which are connected to the elevator body or another
stationary
portion of the elevator.
Fig. 8A represents an embodiment of the invention where non-adjustable
stabilizers suppress the elevator's movement with respect to the bails from
which it is
suspended. Adjustable stabilizers having the ability to rotate are preferable
when the
stabilizers are attached directly to the timing ring, but non-adjustable
stabilizers, such as
brackets 150, 156 can be used when the stabilizer is attached to the body of
the
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elevator. Since the body 42 of the elevator 40 does not move up and down
relative to
the bails like the timing ring 44, the rotating features are not necessary.
Fig. 8A shows. a first stabilizing bracket 150 attached to the first upright
72 which
is connected to the body 42 of the elevator 40. The first bracket comprises a
first
elongated member 152 and a second elongated member 154. On. the opposite side
of
the elevator, a second stabilizing bracket 156 is attached to a second upright
81. Like
the first stabilizing bracket 150, the second stabilizing bracket 156
comprises a first
elongated member 158 and a second elongated member 16Ø Stabilizing brackets
1.50
and 156 may be welded to the tops of their respective uprights. Cut outs 74 in
the
timing ring 44 provide clearance for uprights 72 and 81 to pass through the
timing ring.
The non-adjustable stabilizer could be one piece such as a bracket with two
elongated
members, or two independent elongated members attached to the elevator body.
The
elongated members may comprise a number of shapes and configurations so long
as
they are spaced to accommodate a bail between them.
Fig. 8B illustrates the first member 152 and the second member 154 of the
first
stabilizing bracket 150 in contact with the first bail 54 as well as the first
member 158
and the second member 160 of the second stabilizing bracket 156 in contact
with the
second bail 56 to prevent any pivotal displacement of the elevator relative to
the bails.
This top view provides a clear illustration of the cut outs 74, which allow
the timing ring
44 to move unimpeded by either stabilizing bracket.
While the embodiment. illustrated in Figs. 8A and 8B incorporates a bracket on
each bail with a total of four elongated members, an alternative embodiment
contemplates three, two or even a single elongated member. For example, in the
case
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of an unbalanced elevator with a natural misalignment, the weight distribution
of the
elevator will bias the elevator body to rotate in the same direction relative
to the bails.
In order to prevent this misalignment, one elongated member can be placed on
the
"light side" of the -elevator at one bail. In this way, an elongated member
prevents the
elevator body from rotating in one direction, and the forces tending to
misalign the
elevator body will act against rotation in the other direction.
Hybrids between the illustrated embodiments are also envisioned. For example,
an elevator stabilizer or a set of elevator stabilizers could contain a
combination of
adjustable stabilizing mechanisms and non-adjustable elongated members. One
example would be for the first and third stabilizing mechanisms to be
adjustable, while
the second and fourth stabilizing mechanisms are replaced with non-adjustable
elongated members. The adjustable members and elongated members could be
shaped to cooperate in securing a bail. In this way a bail could be secured
from both
sides by a single adjustment.
This Invention relates to a stabilizer for suppressing unwanted movement in
pipe
handling equipment suspended from bails. Stabilizing an elevator as described
herein
is merely one illustrative embodiment where the invention provides an
advantage, and
the scope of the invention is not limited to such. The stabilizers could be
mounted to
any tool which is suspended by bails. It is apparent that changes and
modifications
may be made without departing from this invention in its broader aspects.
Therefore, the
claims which follow are intended to cover all changes and modifications that
fall within
the scope of the invention.
