Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
1~537~i~
GPMA:005
GRIPPING APPARATUS
This invention relates generally to an apparatus for
S gripping a member. The member may conveniently be in the
form of a cylinder, pipe or tube. More particularlyr this
invention concerns an apparatus having a plurality of jaws
adapted for gripping a cylinder, pipel tube or other mem-
ber. The jaws are in operative association with a body
such that the radial gripping counterforce exerted by the
jaws upon the member, cylinder, pipe or tube is propor-
tional to an axial force upon the cylinder tending to urge
the cylinder in an axial direction with respect to the
body. If the cylinder, pipe or tube attempts to move
axially with respect to the body, an interfacing assembly
urges the jaws~into grippin~ engagement with the cylinder.
In a hydrostatic testing apparatusl it is necessary
to grip a pipe or tube to be hydrostatically tested with
sufficient force to sealingly engage the apparatus upon
the pipe. It is necessary that the hydrostatic testing
apparatus grip the pipe with sufficient force to reduce
or minimize the danger of the pipe slipping out of the
testing apparatusO
~L~S37~
--2--
In the past, it has been common to grip a pipe or
cylinder with hydraulic rams and threaded devices to slips
which apply an outside force to hold a hydrostatic testing
device or cap onto the pipe. Such devices must be tight-
ened to the pipe under substantially zero internal pres-
sure conditions because the slips must be firmly engaged
before the pipe can be pressurized. Tigh~ening during
pressurization of the pipe is impractical and dangerous~
During zero pressure conditions there is no internal fluid
pressure to offset the clamping pressure or gripping force.
Thus, such devices must necessarily stress the outer wall
of the pipe while there is little or no internal pressure
to offset the pipe gripping force. If the initial gripping
force is inadequate, the hydrostatic testing cap will slip
off during internal pressurization of the pipe. If the
initial gripping force is excessive, the pipe may be
deformed or weakened. For pressure testing, the jaws or
slips of such devices must be initially tightened to a
holding force sufficient to withstand test pressure before
the pipe is pressurized.
In prior art jacking systems for offshore oil drilling
platforms, it has been common to grip platform legs with
shear pins, slips or hydraulic rams. Such hydraulic rams
shear pins or slips had to be manually set. The gripping
force upon the platform leg was not necessarily related to
the weight of the platform deck. Oftentimes, a drilling
platform becomes unleveled such that the forces upon other
_- platform legs may increase substantially. Existing devices
for leveling a platEorm ~equire the gripping means to be
released from a platform leg before leveling forces can be
applied. Releasing the gripping means from one platform
leg in order to permit leveling necessarily increases the
danger of the platforr,1 sliding down the platform leg and
l~LS375;8
--3--
creating stress upon the remaining platform legs. Rele~s-
ing the gripper means for leveling purposes creates a
danger of platform system failure.
-
In addition, if one jacking device Eailed, the stress
upon the remaining platform legs could increase substan-
tially. The failure of jacking systems presents a serious
hazard to offshore drilling operations. When the stress
upon prior art jacking devices increases, there is no
mechanism to assure that the gripping ~orce upon the plat-
form leg will also increase in response to such stresses.
Prior art jacking systems are also unsatisfactory
in that many such systems require that shear pin holes be
aligned or that gears be meshed. Thus, the platform may
not be jacked and leveled by moving the platform any
desired distance. The platform may be moved only from one
pin hole to another.
Prior art blowout preventer devices, used to prevent
pipe from being blown out of a hole during drilling
operations typically use hydraulic or threaded systems to
grip the pipe. Such prior art systems must be set by
external gripping forces. Such devices oftentimes cause
hoop stresses upon the pipe when engaged. Because the
gripping force is not related to the force tending to push
the pipe out of the hole, the pipe must be gripped wi~h an
adequate force to prevent a blowout regardless Qf the
existence of any downhole pressure. Thus, under substan-
tially zero downhole pressure conditions, the pipe tends
to be overstressed. Moreover, existing systems may be
slow to engage. Prior art blowout preventer devices
require manual setting and are not automatic or self-
engaging.
1 lS37~
--4--
If a large downhole pressure suddenly de~elops, there
is no mechanism in such prior art blowout preventer devices
to automatically set or increase the gripping force~
Thus, such prior art devices are ineffective to prevent a
blowout unless they have previously been set upon the pipe
with sufficient force to withstand the sudden increase and
in downhole pressure. Such prior art blowout preventers
must also be released in order to permit the withdraw of
casing, coupling or upset portions on the drill string.
Prior art hanging systems for pipe, tubing and casing,
such as systems employed to prevent pipe from being
dropped down into a hole during workover and drilling
operations, commonly referred to as "hangers", and systems
used to grip pipe going in and out of a well, commonly
referred to as "elevators" or "snubbers", re~uired that an
expensive derrick be constructed at the drill site in
order to permit operation of the hanging device. Such
prior art devices typically employ slips that must be
manually reset. In order to pass casing, coupling or
upset portions of the pipe or drill string, such prior art
devices require that the slips be released and expanded to
permit the pipe and casing to be passed. While the slips
are released for the passage of the casing, the safety
hanging device is inoperative. Thus, during such periods,
the pipe or drill string is exposed to the risk of being
dropped into the hole.
The adverse economic consequences and delays encoun-
tered when drill pipe or other devices are dropped into ahole and the difficulty of retrieving the pipe or such
devices requires that a safety hanging apparatus be
available to guard against dripping th epipe at all times
during drilling operations.
~S37S8
--5--
In addition, many prior art hanging devices, includ-
ing snubbers, elevators and hangers, cannot take upward
pressure upon the pipe without impairing their operation.
While prior art arrangements have exhibited a degree
of utility in gripping a pipe, cylinder or tube, room for
significant improvement remains. The problems enumerated
in the foregoing are not intended to be exhaustive, but
rather are among many which tend to impair the effective-
ness of previously known devices for gripping cylinders or
pipes. Other noteworthy problems may also exist; however,
those presented above should be sufficient to demonstrate
that the prior arrangements appearing in the art have not
been altogether satisfactory.
SUMMARY OF A PREFERRED
EMBODIMENT OF THE INVENTION
Recognizing the need for an improved apparatus for
gripping a cylinder or pipe for hydrostatic ~esting for
jacking operations upon offshore drilling platforms for
gripping drill pipe to prevent a blowout and for gripping
drill pipe, tubing and casing in safety hanging systems
and other wellhead workover applications, it is, therefore,
~a general intent in disclosing the present invention to
provide a novel apparatus for gripping a cylinder, pipe
or tube, which minimizes or reduces the problems of the
type previously noted. The present invention has further
useful application in gripping a pipe, tube or cylinder
for other purposes.
It will be appreciated, however, that the invention
can also have application in gripping members which are
not necessarily circular in section or cylindrical in
shape. In this event the gripping jaws of this invention
-h-
would be provided with friction surfaces which general~y
conform to the outer surface configuration of the member
to be gripped. The invention has, however, for the sake
of convenience generally been described herein with
reference to the gripping of cylindrical members of
circular cross-section.
~ feature of the cylinder gripping apparatus resides
in the abili~y to permit the cylinder, pipe or tube to
move in one direction with respect to a body, and to pre-
vent the cylinder from moving in a second opposite direc-
tion with respect to the body. A correlated feature
resides in the ability of the cylinder gripping apparatus
to grip the pipe with a force which is proportional to the
axial force upon the pipe tending to move the pipe with
respect to the body. In an application as a blowout pre-
venter, the cylinder gripping apparatus includes the more
detailed feature of increasing its grip upon the pipe in
response to an increase in downhole pressure tending to
force the pipe out of the well. Thus, a sudden increase
in downhole pressure will result in a sudden increase in
the gripping force upon the pipe.
A feature resides in the provision of floating lugs
which allow jaws to grip a cylinder, pipe or tube with a
proportional gripping force which opposes rotational move-
ment of the cylinder.
~ In an application as a snubber, the invention includes
the feature of back-to-back gripping apparatus which grip
pipe in both axial directions while tubing is installed or
removed. One set of back-to-back apparatus reciprocates
axially to jack the tubing in or out of the well. During
this operation, the tubing is secured at all times in both
3~ axial directions. The gripping means of the present
l~LS~
invention has the additional feature of incorporating lugs
which will not only grip the pipe axially but will grip
the pipe with a force proportional to a rotational torque
for making up or unscrewing joints or pipe.
Of independent significance, the gripping apparatus
includes an interfacing assembly which is more economical
to construct and operate. A more detailed feature resides
in the utilization of force translation lugs to interface
the jaw with the cylinder. The utilization of such force
translation lugs renders the cylinder gripping apparatus
inexpensive to construct and simple to operate.
Yet another feature of the cylinder gripping apparatus
is the provision for an interfacing assembly which permits
the jaw to be easily aligned with the cylinder, even when
the cylinder is not axially centered within the body. The
interfacing assembly permits radial, axial and transverse
movement of the jaw with respect to the body in order to
permit the jaw to correctly align itself upon the cylinder.
In an application as a drilling platform jacking
apparatus, the cylinder gripping apparatus includes the
related feature o~ providing a jacking apparatus which
increases its grip upon the platform leg in response to
increased pressures generated by unleveling of the plat-
form deck or the failure of a jacking apparatus upon
another leg of the platform. This feature reduces the
incidence of failure of the jacking apparatus.
A cylinder gripping apparatus according to a presently
preferred embodiment of the invention intended to substan-
tially incorporate the foregoing features includes a jaw
adapted for gripping a cylinder, a body adapted to axially
receive the cylinder, and an interfacing assembly. The
~5~5i 3
--8--
interfacing assembly is interposed between the jaw and the
body and is adapted to urge the jaw into gripping engage-
ment with the cylinder when the cylinder is ~rged in a
first direction with respect to the body. The interfacing
assembly is adapted to~allow the jaw to release from the
cy,linder when the cylinder is moved in a second direction
with respect to the body.
The interfacing assembly is adapted to provide a
radial gripping force in response to an axial force upon
the cylinder which is proportional to that axial force.
The interfacing assembly is adapted to permit radial,
axial and transverse movement of the jaw with respect to
the body in order to permit the jaw to align itself upon
the cylinder when the cylinder is not perfectly centered
within the axis of the body or when the cylinder is
deformed.
The interfacing assembly may comprise a force trans-
lation lug which is engageably within bearing grooves uponthe jaw and the body.
The interfacing assembly may also comprise a plurality
of generally cylindrical rollers interposed between the jaw
and the body. In this embodiment, the body has an inclined
side wall. The rollers are operable to facilitate the
movement of the jaw relative to the body along the inclined
side wall of the body in order to urge the jaw into grip
ping engagement with the cylinder. Channels adapted to
3n receive the cylindrical rollers may be formed either in
the jaw or in the side wall of the body.
~5~3~75~
g
The interfacing assembly may alternatively comprise
a cam arm pivotally attached to the body having a generally
arcuate cam surface. The jaw may have a groove adapted to
receive the cam surface of the cam arm. The can arm is
operable to urge the jaw into engagement with a cylinder
when the cam arm is rotated with respect to the body.
~~ Employed as a platform jacking apparatus, the cylinder
gripping apparatus may employ two sets of jaws. One set of
the jaws is operable to grip the platform leg while the
other set is released Actuating means or hydraulic cylin-
ders are connected to one set of the jaws to provide a
means for jacking the platform deck up upon the platform
leg.
Examples of the more important features of this inven-
tion have thus been summarized rather broadly in order that
the detailed description thereof that follows may be better
understood, and in order that the contribution to the art
may be better appreciated. There are, of course, additional
features of the invention that will be described hereinafter
and which will also form the subject of the claims appended
hereto. Other features of the present invention will become
apparent with reference to the following detailed descrip-
tion of a presently preerred embodiment thereof in connec-
tion with the accompanying drawings, wherein like reference
numerals have been applied to like elements.
BRIEF DESCRIPTION OF THE DRAWINGS
~ IGURE 1 depicts a side view of an embodiment of a
cylinder gripping apparatus constructed in accordance with
the present invention.
~l53~75~
- 1 o -
FIGURE 2 shows a cutaway end view of the cylinder
gripping apparatus depicted in FIGURE 1.
FIGURE 3 shows a side view of an alternative embodi-
ment of the cylinder gripping apparatus.
Similar to FIGURE 3, FIGURE 4 shows a side view of
the embodiment illustrated in FIGURE 3 depicting the
retainers or stays.
FIGURE 5 illustrates a partially cutaway end view
of the embodiment depicted in FIGURE 4.
FIGURE 6 is a side view of an alternative embodiment
of the cylinder gripping apparatus.
FIGURE 7 is a side view of yet another alternative
embodiment of the cylinder gripping apparatus.
FIGURE 8 illustrates a side view of an alternative
embodiment of the cylinder gripping apparatus.
FIGURE 9 deplcts a partially cutaway side view of an
embodiment of the cylinder gripping apparatus employed as
a safety hanging apparatus for a pipe.
FIGURE 10 shows an enlarged side view of the force
translation lug and the bearing groove in the body.
FIGURE 11 illustrates a cutaway bottom view of the
apparatus shown in FIGURE 10.
FIGURE 12 shows a partially cutaway bottom view of
the apparatus illustrated in FIGURE 9O
~ ~5~7S8
-1 1~
J FIGURE 13 depicts an embodiment of the cylinder grip- `
ping apparatus employed as a drilling platform jacking
apparatus.
DETAILED DESCRIPTION OF A
PREFERRED EMBODIMENT OF THE INVENTION
~~ Turning now to the drawings in Figure 1I there is
depicted a side view of a portion of a cylinder gripping
apparatus 200. The cylinder gripping apparatus 200 com-
prises a body 201, a jaw 202 and an interfecting assembly
203. The body 201 is only partially shown in Figure 1.
As best shown in Figure 2, the jaw 202 has a friction
surface 204 adapted for gripping a cylinder 205. The fric-
tion surface 204 may comprise serrations, teeth, a smooth
friction surface, or other conventional friction surfaces.
With reference to Figure 1, the interfacing assembly
203 may comprise floating force translation lugs 206. The
intlerfacing assembly also comprises a resilient member,
elastic member or spring 207. The elastic mernber 207 is
connected to the jaw 202 at a firs-t spring anchor point
208. The elastic member 207 i5 connected to the body 201
at a second spring anchor point 209.
The floating force translation lugs 206 are floating
in the sense that the lugs 206 are unconnected to either
the body 201 or the jaw 202. The lugs 206 fit into first
bearing grooves or sockets 210 formed in the jaw 202. The
other end of the lugs 206 fit into second bearing grooves
or sockets 211.
As shown in Figure 2, the lug 206 has a first arcuate
end or curved end 212 and a second arcuate or curved end
:~ ~S~7S13
-12-
213. The first arcuate end 212 is adapted to fit into the
first bearing groove 210. Similarly, the second arcuate
end 213 is adapted to fit into the second bearing groove
211.
As best shown in the side view depicted in Figure 1,
the forced translation lugs 206 are anyularly disposed
between the body 201 and the jaw 202. The first bearing
groove 210 has a first arcuate or curved bearing surface
214 which tapers to a sloped forward surface 215. The
sloped forward surface 215 allows the lug 206 to rotate
in a first sense inside the first bearing groove 210. In
Figure 1, the first sense of rotation is clockwise with
respect to the jaw 202.
Similarly, the second bearing groove 211 comprises a
second arcuate or curved bearing surface 216 which tapers
to a sloped or planar rearward surface 217. The sloped
rearward surface 217 permits the lug 206 to rotate in a
first sense with respect to the body 201.
The lugs 206 are floating and~thus unconnected to
the body 201 or the jaw 202. Therefore, it is desirable
to provide a means for compressively engaging the jaw 202
toward the body 211 in order to hold the lugs 206 within
the first and second bearing grooves 210 and 211. In the
present instance, this is essentially accomplished by the
elastic member 207. When the jaw 202 is not engaged
against a cylinder 205, the elastic member 207 tends to
urge the jaw 202 toward the body 201, thus holding the
lugs 206 in engagement within the first and second bearing
grooves 210 and 211.
~l S7~17~
-13-
It will be appreciated that some actuating means may
be provided to ~rge the jaw 202 into initial engagement
with the cylinder 205. When the jaw 202 is engaged
against a cylinder 205 and an axial force urges the
cylinder 205 in a forward direction, or to the right in
Figure 1, then the lugs 206 will tend to rotate in a
second sense, or counterclockwise in Figure 1. The
tendency of the lugs 206 to rotate in a second sense will
tend to urge the jaw 202 into gripping engagement with the
cylinder 205. The gripping force between the jaw 202 and
the cylinder 205 will be proportional to the axial force
exerted upon the cylinder 205. Thus, the force transla-
tion lugs 206 provide a radial coun`terforce in response to
the axial force upon the cylinder.
When the cylinder 205 is not perfectly axially aligned
with respect to the body 201, it is desirable to permit
the jaw 202 to move in a direction transverse to the axis
of the body 201. As best shown in Figure 2, it is desira-
ble to allow the jaw 202 to move transversely, i.e., tothe left or right, in order to allow the friction surface
204 to engage the cylinder 205. The curved end~ 212 and
213 cooperate with the first opposing face 218 of the jaw
202 and the second opposing face 219 of the body 201 to
permit a transverse displacement of the jaw 202 from an
initial axially aligned position to a displaced position
either to the right or to the left of Figure 2. Thus, the
floating lug 206 permits the friction surface 204 of the
jaw 202 to engage the cylinder 205 even when the cylinder
205 is not preferably axially aligned within the body 201.
Thus, the floating nature of the lug 206 which is
interposed between the jaw 202 and the body 201 permits
movement between the jaw 202 and the body 201 with at
least three degrees of freedom~ That is, the j~w 202 may
LS37S;13
14~
move axially, radially and transversely with respect to
the body 201. These degrees of freedom of movement that
are permitted the jaw 202 with respect to the body 201
- facilitate the effective engagement of the jaw 202 against
the cylinder 205 even for imperfectly aligned cylinders
205.
In some applications, such as a wellhead snubber
apparatus, it may be desirable to grip a pipe, tube or
cylinder 205 to prevent rotation of the pipe, tube or
cylinder 205 about the axis o~ the body 201. As shown in
Figure 2, the floating lug 206 may be positioned in offset
position 400 (shown as a broken line). In the offset
position 400, the lug 206 will tend to oppose clockwise
rotation of the pipe 205. The gripping force of the jaw
202 upon the pipe 205 will be proportional to the clockwise
torque upon thepipe 205. Similarly, counterclockwise
rotation of the pipe 205 may be prevented by a jaw 202
with the lug 206 offset in an opposite directlon, or to
the right in Figure 2 (not shown).
It will be appreciated that a second cylinder gripping
apparatus 200 may be connected to the same pipe 205 as a
~irst gripping apparatus 200 with a set of lugs 206 offset
in an opposite direction in order to prevent both clockwise
and counterclockwise rotation of the same pipe 205.
Turning now to Figure 3, another embodiment of the
interfacing assembly 203 is shown. The interfacing assem-
bly 203 comprises floating lugs 220 interposed between the
body 201 and the jaw 202. The floating lugs 220 may be
fabricated differently from the lugs 206 illustrated in
Figures 1 and 2. ~s best shown in Figure 5, the lug 220
has a first curved or arcuate end 221 and a second curved
or arcuate end 222. The first curved end 221 is wider
~.S~)758
-15-
than the second curved end 222. The first curved end 221
may be substantially the same width as the jaw 202~ As
best shown in Figure 5, the first bearing groove 210 may
extend across substantially the entire width of the jaw 202.
s
The first end 221 of the lug 220 may be held within
the first bearing groove 210 by a set of first stays or
retaining means 223. The first stays 223 are fixedly held
against the jaw 202 by fastening means 224. Faster.ing
means 224 may comprise a bolt, screw, pin, or other con-
ventional fastening mechanisms.
Similarly, the second end 222 of the lug 220 may be
held within the second bearing groove 211 by a set of
second stays or retaining means 225. The second stays 225
are fixedly held against the body 201 by fastening means
226. Fastening means 226 may comprise a bolt, screw, pin,
or other conventional fastening mechanisms.
Fastening means 224 and 226 are connected to the jaw
202 and the body 201, respectively. The first and second
stays 223 and 225 are not connected to the lug 220. This
can best be seen with reference to Figure 4. The first
and second stays 223 and 225 are adapted to cover at least
a portion of the cross-sectional area of the first and
second bearing surfaces or grooves 210 and 211 in the jaw
202 and the body 201, respectively. The first and second
stays 223 and 225 are adapted to laterally retain the lug
220 within the first and second bearing grooves 210 and
211 r while leaving the lugs 220 free to rotatively pivot
within the bearing grooves 210 and 2110
The stays 223 and 225 may be omitted, as shown in
Figure 3, and are not essential for the operation of the
cylinder gripping apparatus.
~1 ~537~8
-16-
Thus, as shown in Figure 3, the first and second
curved ends 221 and 222 of the lug 220 cooperate with
first and second opposing faces 218 and 219 of the jaw 202
and the body 201, respectively, to permit a transverse
displacement of the cylinder 205 from an initial axially
aligned position to a displaced position. This degree of
freedom of movement of the ~aw 202 in the transverse direc-
tion permits the jaw 202 to more evenly engage the cylinder
205 when the cylinder 205 is not perfectly axially aligned
within the body 201.
As shown in Figure 3, the opposing face 218 of the
jaw 202 has a curved surface or bearing groove 210 adapted
to receive the curved end 221 of the floating lug 220.
An elastic member 207 tends to urge the jaw 202 toward
the body 201 in order to hold the lugs 220 into engagement
within the first and second curved surfaces 210 and 211~
A compression member or spring 227 tends to urge the jaw
202 into engagement with the cylinder 205. As shown in
Figure 3, the compression member 227 is interposed between
the front of the body 201 and the jaw 202.
Actuatiny means 228 is connected to the lug 220 for
rotationally pivoting the lug 220. Actuating means 228
may comprise a handle. Actuating means 228 may be used
to rotationally pivot the lug 220 in a first sense, or
clockwise as shown in Figure 3, to permit the jaw 202 to
disengage the cylinder 205.
It will be noted that the elastic member 207 tends
to urge the jaw 202 radially outwardly with respect to the
body 201, thus urging the lugs 22n into operative engage-
ment with the ~irst and second bearing grooves 2~0 and
~S37~8
-17-
211. When the cylinder 205 is removed from the body 201,
the elastic member 207 tends to hold the jaw 202 and the
body 201 into engagement with the lu~s 220.
As shown in Figure 4, the first bearing groove 210
comprises a first curved or arcuate bearing surfaces 214
~hich tapers to a sloped or planar forward surface 215.
Similarly, the second bearing groove 211 comprises a
second curved or arcuate bearing surface 216 which slopes
to a planar or sloped rearward surface 217.
It will be appreciated that a floating force trans-
lation by 206 may be constructed with a first arcuate,
curved or spherical end 212 as shown in Figures 1 and 2,
and with a second end fashioned in accordance with the
embodiment described above with reference to Figures 3,
4 and 5.
Referring to Figure 6, a side view of another embodi-
ment of the present invention is illustrated. The inter-
facing assembly 203 is interposed between the sidewall of
the body 201 and the jaw 202. In the present instance,
the interfacing assembly 203 has curved or arcuate sur-
faces 229 which engage an opposing face 230 of the side-
wall of the body 201. The curved or circular surfaces 229
form the outer surEace of generally cylindrical or circular
rollers 231. In a preferred embodiment, the rollers 231
are formed in the shape of cylindrical rods.
The rollers 231 are adapted to fit within channels 234
in the jaw 202. The channels 234 are formed transversely
along the inner surface 235 of the jaw 202. As shown in
Figure 6, the inner surface 235 of the jaw 202 is inclined
or sloped. Similarly, the opposing face 229 of the side-
wall of the body 201 is similarly sloped or inclined.
~i;37.~8
-18-
The rollers 231 are floating, and are thus ~ncon-
nected to either the jaw 202 or the body 201. The elas-
tic member 207 tends to urge the jaw 202 radially out-
wardly toward the sidewall of the body 201. Thus, the
S elastic member 207 tends to hold the rollers 231 in the
channels 234.
-
The rollers 231 facilitate the movement of the jaw
202 along the planar sloped opposing face 230 of the body
201. The rollers 231 are operable to facilitate the move-
ment of the jaw 202 relative to the body 201 along the
inclined inner surface 230.
The inclined inner surface 230 is adapted to urge the
jaw 202 into engagement with the outer surface of the
cylinder 205 when the jaw 202 is urged rearwardlyr or to
the right in Figure 6, with respect to the body 201. A
compression memberr resilient member or spring 227 is
adapted to urge the jaw 202 rearwardly with respect to the
body 201.
Actuating means 232 is pivotally connected to the
body 201 at a pivot point 233. Actuating means 232 may
comprise a handle, in a preferred embodiment. Actuating
means 232 is a~apted to urge the jaw 202 generally for-
wardly, but that is to the left in Figure 6, with respect
to the body 201~ Thus, actuating means 232 may be used
to disengage the jaw 202 from the cylinder 205.
The rollers 231 may be confined to the channels 234
by stays 225 (not shown).
~537~ii8
,g
Because the rollers 231 are floating, the jaw 202 is
permitted to move transversely with respect to the body
201. This transverse movement of the jaw 202 permits the
jaw to grip the cylinder 205 even when the cylinder 205 is
not axially centered within the body 201. Thus, the
curved surface of the rollers 231 is cooperable with the
opposing face 230 of the body 201 to permit a transverse
displacement of the jaw 202 from an initial axially aligned
positioned to a displaced position.
It will be appreciated that the channels 234 are pref-
erably generally cylindrically shaped in substantial
correspondence with the shape of the rollers 231. A first
boss, finger or projection 236 limits the transverse
movement of the jaw 202 with respect to the body 201. The
boss 236 prevents the jaw 202 from completely slipping out
of the cylinder gripping apparatus 200. Similarly, a
second boss, finger or projection 237 is formed UpGn the
rear of the jaw 202.
Figure 7 illustrates an alternative embodiment of the
interfacing assembly 203 interposed between the jaw 202
and the body 201.
In the present instance, generally cylindrical roller
238 have curved, arcuate or generally round surfaces 239
which are cooperable with an opposing planar inclined face
240 of the jaw 202 to permit movement of the jaw 202 with
respect to the body 201. The rollers 238 fit within
generally cylindrically shaped channels 241 formed trans-
versely along the inclined or sloped inner surface 230 of
the sidewall of the body 201. The rollers 238 permit the
jaw 202 to move transversely with respect to the body 201
in a manner similar to the interfacing assembly described
with reference to Figure 6.
~l ~S37~
-20-
In other respects the interfacing assembly 203
depicted in Figure 7 is constructed and operated similar
to the interfacing assembly 203 described with reference
to Figure 6.
Turning now to Figure 8, the interfacing assembly
- ~F- 203 is interposed between the body 201 and the jaw 202.
In the present instance, the interfacing assembly 203 has
a curved surface 242 which interfaces with an opposing
face 243 of the jaw 202. The opposing face 234 of the jaw
202 is located generally opposite to the friction surface
204 of the jaw 202.
The opposing face 234 of the jaw 202 has a curved
surface or groove 244 formed in a position generally in
correspondence with the curved surface 242 of the inter-
facing assembly 203. The curved surface 242 of the
interfacing assembly 203 is cooperable with the opposing
face 234 of the jaw 202 to permit the jaw 202 to move not
only radially and axially with respect to the body 201,
but also transversely with respect to the body 201. Thus,
if the cylinder 205 is not axially centered within the
body 201, the curved surface 242 will permit the jaw 202
to move from an initial axially centered position to a
displaced position in correspondence with the uncentered
or displaced position of the cylinder 205. Thus, the
interfacing assembly 203 permits the jaw 202 to be dis-
placed transversely with respect to the body 201 in order
to more effectively engage the cylinder 205 when the
cylinder 205 is deformed or uncentered within the body
201.
. The interfacing assembly 203 further comprises a cam
arm or force translation arm 245 which may be pivotally
35 connected to the body 201 at a second pivot point 246.
~s~
-21-
The cam arm 245 is operable to urge the jaw 202 into
engagement with the outer surface of the cylinder 205 when
the cam arm 245 is rotated in a second sense, or counter-
clockwise in Figure 8, with respect to the b~dy 201.
Elastic members or springs 247 are connected to
the jaw 202 at first spring anchor points 248 and are
connected to the body 201 at second spring anchor points
249. The elastic members 247 tend to urge the jaw 202
radially outwardly with respect to the body 201. Thus,
the elastic members 247 tend to urge the ~aw 202 into .
engagement with the generally arcuate cam surface 242 of l:
the cam arm 245.
In the present instance the jaw 202 has a forward
alignment lip 250 and a rear alignment lip 251. The
alignment lips 250 and 251 are connected to the forward l:
and rear edges of the jaw 202 respectively, as shown in
Figure 27. The alignment lips 250 and 251 operate to
disengage the entire jaw 202 from the cylinder 205 in the
event that either the forward or rear end of the jaw 202
does not initially disengage from the cylinder 205. If
the cam arm 245 is rotated in a first sense, or clockwise
in Figure 8, with respect to the body 201, the jaw 202
will be urged radially outwardly from the cylinder 205 by
the elastic members 247. In the event that the rear
portion of the jaw 202 does not initially disengage from
the cylinder 205, the forward align~ent lip 250 will
contact the inner surface 219 of the body 201. Thus,
further rotation of the cam arm 245 in a first sense with
respect to the body 201 will cause the jaw 202 to pivot
about the point where the forward alignment lip 250
contacts the inner surface 210 of the body 201 and will
cause the rear portion of the jaw 202 to disengage from
the cylinder 205.
~5375Z3
-22-
In the present instance, the cam arm 245 has actua-
tion means or a handle 252 connected to it~ An elastic
member or spring 253 may be connected between the handle
252 and the body 201. The elastic member 253 will tend
to urge the cam arm 245 to rota~e in a second sense with
respect to the body 201 and thus urge the jaw 202 into
engagement with the cylinder 205.
It will be appreciated that the interfacing assem-
blies 203 illustrated in Figures 3, 6, 7 and 8 are adapted
to provide a radial counterforce in response to an axial
force upon the cylinder. If an axial force is exerted
upon the cylinder 205 when the jaw 202 is in engagement
with the cylinder 205, and the cylinder 205 is urged to
the right in Figures 3, 6, 7 and 8~ the interfacing
assemblies 203 will provide a radial counterforce or
gripping force which is proportional to the axial ~orce
exerted upon the cylinder 205.
It will also be appreciated that, similar to Figure
8, the inter~acing assembly 203 illustrated in Figures 1,
2, 3, 4 and 5 ~ay be pivotally connected at one end to
either the jaw 202 or the body 201.
In Figure 9, an embodiment of the present cylinder
gripping apparatus is shown for use in connection with
a safety hanger or blowout preventer apparatus for use
in connection with drilling operations. The embodiment
illustrated in Figure 9 may also have utility as a snubber~
3~
As illustrated in Figure 9, the body 201 has an upper
cylinder, pipe or tube passageway or opening 254 and a
lower pipe, tube or cylinder passageway or opening 255.
The body 201 is adapted to axially receive the pipe, tube
or cylinder 205. The jaws 202 have a ~riction surface 204
adapted to grip the drill pipe 205.
~53758
-23-
In the present instance, the interfacing assembly 203
comprises angularly disposed floating force translation
lugs or arms 256. The lug 256 is floating because it is
unconnected to the body 201 or the jaw 202. The lug 256
has a ~irst curved surface or arcuate surface 257 on one
end and a second curved or arcuate surface 258 on the other
end. The first curved end 257 is adapted to fit ~ithin a
first bearing groove 259. Similarly, the second curved
end 258 is ~dapted to fit within a second bearing groove
260. The bearing grooves 259 and 260 are constructed
similar to the bearing grooves 211 and 214 illustrated in
Figures 3, 4 and 5. For example, as best shown in Figure
10, the second bearing groove 260 comprises a second
curved or arcuate bearing surface 261 which tapers to a
generally planar or inclined surface 262.
As best shown in Figure 10, the lug 256 is floating
in the sense that it is not connected to the body 201.
First and second retaining means or stays 265 and 266
are connected or fastened to the jaw 202 and the body
201 respectively. The stays 265 and 266 retain the lugs
256 when the pipe 205 is withdrawn from the body 201, as
will be more fully described below.
Referring-to Figure 10, the stay 266 has an aperture
or opening 263. The aperture 263 is adapted to receive a
projection or pin 264 connected to the lug 256. As best
shown in Figure 11, the pin 264 is connected to the lug
256 and extends through the aperture 263 in the stay 255.
When the jaw 202 engages the pipe 205, the lug 256 engages
the grooves 259 and 260. When the lug 256 is engaged with
the grooves 259 and 260, the pin 264 does not contact the
stay 266. As best shown in Figure 10, the aperture 263 is
larger than the pin 264. Thus, the lug 256 is essentially
7~S8
2~-
floating. The pin 264 cooperates with the stay 266 to
retain the lug 256 when the pipe 205 is withdrawn from
the body 201.
As best shown in Figures 10 and 11, the sta~ 266 is
connected to the body 201 by fastening means 267. Fasten-
ing means 267 may comprise a bolt, screw, pin or other
conventional fastening mechanisms. Referring to Figure 9,
the first stay 265 is similarly connected to the jaw 202.
In addition, the lug 256 has a corresponding pin 268 which
is adapted to fit within an aperture in the first stay
265. It will be appreciated that either end of the lug
256 may be pivotally connected to the body 201 or jaw 202.
The operation of the interfacing assèmbly 203 illus-
trated in Figures 9 through 12 and providing a radial
counterforce or gripping force upon the pipe 205 in
response to an axial force upon the pipe 205 is similar
to the inter~acing assemblies 203 described above with
reference to Figures 1 through 8.
The interfacing assembly 203 illustrated in Figure 9
further comprises a jaw housing 269. The jaw housing 269
has arm passage openings 270 which permit the lugs 256 to
pass through the jaw housing 269. A compression member
or spring 271 is provided between the body 201 and the jaw
housing 269. The spring 271 tends to urge the jaw housing
269 downward as shown in Figure 9. This tends to urge the
jaws 202 into engagement with the pipe 205.
A wiper 272 is provided to remove dirt, grime and
other foreign matter from the surface of the pipe 205.
The wiper 272 operates to prevent dirt and other matter
upon the surface of the pipe 205 from interfering with the
gripping surface 204 of the ~aws 202.
758
-25-
A releaserr jaw releasing cylinder or cylinder
means 273 is connected to the body 201. The releaser ~
has a rod 274 shown in Figure 9 in the retracted positio
The rod 274 is operable to be extended from the releaser
273 so that it contacts the jaw housing 269 and urges it
upward. The releaser 273 is adapted to compress the
spring 271 and thus disengage the jaw 202 from the pipe
205.
It will be appreciated that a second similar body
275 may be stacked with the body 201 to provide more than
one set of jaws 202 to grip the pipe 205. The pipe 205 is
shown in Figure 9 with a casing 276. A second set of jaws
provided in the second body 275 would operate to grip the
pipe 205 when the casing 276 was passed through the body
201.
Employed as a safety hanger apparatus, the embodiment
of the invention illustrated in Figure 9 would permit the
drill pipe 205 to be removed from the hole by ~oving it
upward. However, if the drill pipe 205 was dropped, the
jaws 202 would automatically engage the drill pipe 205 and
prevent it from falling into the hole (not shown). I'he
jaws 202 are adapted to permit the drill pipe 205 to be
moved upwardly~in Figure 9, and are adapted to prevent the
drill pipe 205 from being dropped down the hole or for
moving downwardly in Figure 9.
It will be appreciated that the embodiment o the
invention illustrated in Figure 9 may have useful applica-
tion for other types of pipe, tu~es or cylinders. The
present invention is not intended to be limited to drill
pipe. 5
1 ~53~SB
-26-
In the event that it is desired to drill and move
the drill pipe 205 downwardly, a similar body 201 may be
employed as a blowout preventer by turning ~he body 201
upside down from the position shown in Figure 9. In such
a position, the jaws would permit the drill pipe 205 to be
drilled down into the hole, but would not allow the drill
_ar pipe 205 to be blown out of the hole even in the event of
a sudden increase in downhole pressure. The gripping
force of the jaws 202 upon the drill pipe 205 will be
proportional to the downhole pressure. Thus, the gripping
force of the ~aws 202 upon the dril~ pipe 205 will increase
in proportion to any increases in the downhole pressure.
Thus, a great safety feature is achieved by the present
invention because a sudden increase in downhole pressure
will be immediately offset by an increase in the radial
counterforce or gripping force of the jaws 202 upon the
drill pipe 205.
The releaser 273 is operable to disengage the jaws
202 when it is desired to move the drill pipe 205 in a
direction opposite to the direction of movement permitted
by the jaws 202.
Figure 13 depicts an embodiment of the cylinder grip-
ping apparatus having utility as an offshore drilling plat-
form deck jacking apparatus.
Although any of the interfacing assemblies previously
described with reference to Figures 1 through 12 may be
used to interface jaws with a body, the illustrated embodi-
ment of the platform jacking apparatus 277 comprises a
first jaw 21, a first arm 22, a first pivot point 23, a
second pivot point 2~, a first extension 117, a first
guide or synch sleeve 123, a first shoe or fastening means
119, a first actuation means 121, a first shaft 125 and a
first fastening means 127.
i3~58
-27-
Similarly, a second jaw 58, second arm 57, third
pivot point 60, fourth pivot point 59, second extension
118, second guide or synch sleeve 124, second shoe 120,
second actuation means 122, second shaft 126 and second
fastening means 128 operate in a similar manner.
In the embodiment shown in Figure 13, a third arm
~,~
278 is pivotally connected to the body at a fifth pivot
point 279. The third arm 278 is pivotally connected to
the first jaw 21 at a sixth pivot point 2800 A fourth arm
281 is pivotally connected to the body 290 at an eighth
pivot point 282. The fourth arm 281 is connected to the
second jaw 58 at an eighth pivot point 283. The body 290
is connected to a platform 284 in the present instance,
the platform 2~4 comprises a conventional offshore drilling
platform. The first and second jaws 21 and 58 comprise a
first set of jaws which are adapted to grip a platform leg
285. A first compression member or spring 286 is inter-
posed between the first jaw 21 and the body 290. The
spring 286 is adapted to urge the first jaw 21 into engage-
ment with the platform leg 285. A second compression
member or spring 287 similarly urges the second jaw 58
into engagement with the platform leg 285. A third jaw
288 and a fourth jaw 289 comprise a second set of jaws
adapted to grip the platform leg 285. The second set of
jaws 288 and 289 operate in a manner similar to the first
set of jaws 21 and 58. The body 290 has a guide sleeve
291 which is adapted to receive a jaw housing 292 which is
annularly shaped as sho~n in Figure 32. The jaw housing
292 is adapted to axially receive the platform leg 285.
The body 290 is similarly adapted to axially receive the
platform leg 285. The jaw housing 292 is adapted to
reciprocally slide within the guide sleeve 291 of the body
290. Actuation means or cylinder means 293 is connected
~ 1~3~
-28-
to the body 290. Actuation means 293 has a shaft 294
which is operable to reciprocally extend or retract within
actuation means 293. The shaft 294 is connected to the
jaw housing 292
The platform 284 may be jacked up the platform leg
285 by allowing the second set of jaws 288 and 289 to
engage the platform leg 285 while the shafts 294 are in
the retracted position. When the shafts 294 are in the
retracted position, the jaw housing 292 will be retracted
within the guide sleeve 291 of the body 290. Thus,
cylinder means 293 may be used to extend shafts 294 to
push the jaw housing 292 downwardly with respect to the
body 290. Thus, the body 290 and the platform 284 are
raised with respect to the platform leg 285 while the jaw
housing 292 remains stationary with respect to the plat-
form leg 285.
In Figure 13, the shaft 294 is shown in the fully
extended position. The shaft may be e~tended a distance
X as shown in Figure 13. Thus, for each motion, the
platform 284 may be jacked up a distance X.
When the shaft 294 has reached the fully extended
position, the first set of jaws 21 and 58 are allowed
to engage the platform leg 285. Thus, the first set of
jaws 21 and 58 will hold the platform 284 in position as
the shafts 294 and the second set of jaws 288 and 289 are
retracted within the guide sleeve 291. It will be appre-
ciated that both the first set of jaws 21 and 58 and the
second set of jaws 288 and 289 will permit the platform
leg 285 to be moved in one direction with respect to the
body 290 and the jaw housing 292, but will not permit the
platform leg 285 to be moved in an opposite direction with
respect to thebody 290 or the jaw housing 292.
37~13
-29-
The first and second springs 286 and 287 are adapted
to insure that the first set of jaws are urged generally
radially inwardly with sufficien~ force to insure that the
first set of jaws 21 and 58 maintain contact with the
platform leg 285. Thus, if the second set of jaws 28~ and
289 should fail for any.reason, the first set of jaws 21
and 58 would automatically grip the plàtform leg 285 with
a gripping force proportional to the weight of the platform
284 or`proportional to the stresses upon the platform leg
285. Similarly, a third and fourth spring or compression
member 295 and 296 urge the second set of jaws 288 and 289
into engagement with the platform leg 285.
In the present instance, a plurality of wipers 297 is
provided between the jaw housing 292 and the guide sleeve
291 and the platform leg 285. The wipers 297 tend to keep
sea water or other unwanted matter from contaminating the
interior of the guide sleeve 291. Air vent ports 298 pro-
vide fluid communication between the air within the inte-
rior of the guide sleeve 291 and the external atmosphere.
A plurality of second wipers 299 is provided betweenthe body 290 and the platform leg 285.
In the illustrated embodiment, the first and third
arms 22 and 278 are pivotally connected to a first spline
or rib 300 formed from the body 290. Similarly, the
second and fourth arms 57 adn 281 may be pivotally con-
nected to a second spline or rib 301 formed from the body
290~
The actuation means 121 and 122 may also comprise a
first releaser operable to release the first set of jaws
21 and 58 from engagement with the platform leg 285.
Similarly, actuation means 302 and 304 may comprise a
1.~537S~3
-30
second releaser operable to release t~le second set of jaws
288 and 289 from engagement with the platform leg 285.
The second releaser 302 and 304 is operable to disengage
the second set of jaws 288 and 289 to permit the retraction
of the jaw housing 292 within the guide sleeve 291.
The platform 284 may be lowered, ~also by synchronized
operation of first and second releasers 121 and 122, and
302 and 304, in a manner generally opposite to that
described above with reference to jacking the platform
284 up.
It will be appreciated that the cylinder gripping
apparatus described above may find utility in any applica~
tion where it is desirable to grip a cylinder, rod pipe or
tube to keep the cylinder, rod pipe or tube from going in
an unwanted direction. The cylinder gripping apparatus
may be employed with utility to hold the end of a pipe to
be forged during the process of upsetting tubing. Alter-
natively, the cylinder gripping apparatus may find utilityin holding tubing during the process of belling where a
mandrel is inserted and welded to a pipe or tube. Simi-
larly, any operation that requires a pipe, tube or cylinder
to be held or gripped where large axial forces tend to
urge the pipe, tube or cylinder in an unwanted direction.
SUMMARY OF ADVANTAGES OF THE INVENTION
It will be appreciated that in constructing a cylin-
der gripping apparatus according to t~e present invention,certain significant advantages are provided.
31 1~i3758
-31-
In particular, a cylinder gripping apparatus according
to the present invention permits a cylinder, pipe or tube
to be held by a gripping force which is proportional to an
axial force tending to urge the cylinder, pipe or tube in
an unwanted direction. A cylinder gripping apparatus
according to the present invention provides an interfacing
assembly which dev~lops a radial counterforce or gripping
force in response to an axial force upon the cylinder
which is proportional to the axial force. Thus, as the
axial force tending to urge the cylinder in an unwanted
direction increases, the gripping force will increase
proportionally in response to the increase axial force.
In addition, a cylinder gripping apparatus according
to the present invention provides an interfacing assembly
which is more economically constructed and which is
adapted to withstand greater forces between the jaw and
the body. The elimination of arms which are pivotally
connected by pins to the jaw and the body eliminates the
requirement that the pins be sufficiently strong to
withstand the forces between the arm and the body.
Moreover, the cylinder, pipe or tube need not be
perfectly centered within the body. A cylinder gripping
apparatus according to the present invention permits the
jaw to move transversely with respect to the axis of the
body and thereby align into engagement with a cylinder
which is deformed or which is not perfectly centered
within the body.
A cylinder gripping apparatus according to the present
invention includes the further advantage of providing an
interfacing assembly which may be used in connection with
a hydrostatic testing apparatus for high pressure testing.
The interfacing assembly is adapted to withstand greater
forces than the embodiment disclosed in the prior art.
~s~s~
-32-
A cylinder gripping apparatus according to the present
invention includes the further advantage of providing
utility as a snubber, safety hanging apparatus or blowout
preventer for use in connection with wellhead operations.
In such an application, the cylinder gripping apparatus
provides the advantage of jaws which do not have to be
completely released from the pipe in order to pass
~~ couplings. Thus, the risk of dropping the pipe or having
a blowout while couplings are being passed is avoided. A
blowout preventer, snubber or safety hanging apparatus
constructed according to the present invention will pro-
vide a safety feature in that the gripping force generated
will be proportional to the axial and Torsional forces
upon the pipe.
1 5
A cylinder gripping apparatus according to the present
invention may employ offset floating lugs which provide the
advantage of a gripping force which is also proportional
to the rotational forces or torque upon the cylinder, tube
of pipe being gripped. The offset floating lugs a~t as
tongs to prevent rotation, in addition to gripping the
pipe to prevent axial movement.
A platform jacking apparatus constructed in accordance
with the present invention will provide a safe method of
jacking drilling platforms providing a gripping force upon
the platform leg which is proportional to the weight of
the drilling platform.
Leveling of a drilling platform is simple and safe. A
jacking distance of a fraction of an inch may be achieved,
if desiredl because one set of jaws can grip the platform
leg at any point along the leg, while actuation means can
be used to slide the platform any desired distance along
the platform leg. Gripping is automatic. The jacking
~.~L53~Si~
-33-
distance is not constrained by any requirement that shear
pin holes be aligned or that gears be meshed. The plat-
form may be jacked up or leveled without completely
releasing any one of the platform legs.
s
Thus, it is apparent that there has been provided in
accordance with the invention, a cylinder gripping appara-
tus that substantially incorporates the advantages set
forth above. Although the present invention has been
described in conjunction with specific forms thereof r it
is evident that many alternatives, modifications, and
variations will be apparent to those skilled in the art
in light of the ~oregoing disclosure. Accordingly, this
description is to be construed as illustrative only and is
for the purpose of teaching those skilled in the art the
manner of carrying out the invention. It is to be under-
stood that the forms of the invention herewith shown and
described are to be taken as the presently preferred
embodiment. Various changes may be made in the shape,
size and arrangement of parts. For example, equivalent
elements or materials may be substituted for those illus-
trated and described herein, parts may be reversed, and
certain features of the invention may be utilized indepen
dently of the use of other features, all as would be
apparent to one skilled in the art after having the
benefit of this description of the invention.
3S
