Note: Descriptions are shown in the official language in which they were submitted.
5-
Backgro~nd of the Invention
The invention pertains particularly to wellhead
connectors of the type which are connected to subsea wellheads
to provide a means for mounting blowout preventor stacks or
other apparatus on such wellheads. ~lowever, in its broader
aspects, the invention may be more generally applied to systems
for connecting two tubular bodies in generally coaxial align-
ment. Such wellhead connectors typically include latches
carried on some type of generally tubular main body. The
latches may be extended radially inwardly, either by a pivotal
type movement or a rectilinear type movement, to engage coop-
erative profiles on the wellhead to latch the main body to the
wellhead. The latches and cooperative wellhead profiles are
typically configured, i.e. with mating inclined surfaces, so
that, at least in theory, as the latches are urged radially
inwardly into tighter engagement with the wellhead, the con-
nection is also tightened longitudinally, a firm connection
being important for any number of reasons well known in the art.
Accordingly, various systems have been devised for so urying
the latches radially inwardly w~th a high mechanical advantage.
However, it has been found that, in prac~ice, the application
of high radial forces to the latches with such systems simply
does not result in the tight connection between the connector
~ody and wellhead which should theoretically result.
It is believed that at least one reason for this un-
desirable phenomenon is that the industry standards concerning
wellhead materials require metalurgical properties which,
while making the wellhead resistant to corrosion, etc., also
necessitate the use of a relatively soft metal in the wellhead.
Then, the high radial forces being applied to the latches,
rather than effectively utilizing the inclined surfaces on the
latches and wellhead to tighten the connection longitudinally,
may simply cause the latches to dig into and deform the wellhead
material withou~ effecting any further longitudinal movement.
r ~D
s
Summary of the Invention
The connector apparatus of the present invention includes
a generally tubular main body with latch means carried thereby
for generally radial extension and retraction toward and away
from a wellhead configured to mate with said latches.
Additionally, the main body of the connector carries support
means radially extendable and retractable at least partially
independently of the latch means. The support means are
configured and arranged so that, when radially extended, they
tighten the connection between the wellhead and the connector
body with a wedging action. The apparatus is further provided
with actuator means for extending the latches and support means
successively radially toward the wellhead.
Because of the provision of the separate support means and
their extension successively after the latches, the problem of
defo~mation of the material of the wellhead can be avoided and
a firm connection achieved. More specifically, the latches can
be extended to substantially their full radially inner limits
into a latching position with respect to the wellhead without
the need for the exertion of any substantial longitudinal
forces between the latches and wellhead. Thus, the latches are
placed in their latching position without any danger of digging
into the wellhead material. The support means may be partially
radially extended along with the latches. In any event, they
are subse~uen~ly extended or further extended to tighten
the engagement between the latches and wellhead in the longi-
tudinal direction. Because the latches are already in their
radially inner positions, there is still no danger of them
digging into the wellhead. Rather, the major relative radial
movement which tightens the connection longitudinally is be-
tween the support means, the latches, and the body on which they
are carried, all of which can be formed of sufficiently hard
materials with improved friction characteristics.
In one preferred embodiment of the invention, the latches
comprise a set of latch dogs spaced circumferentially from one
another about the connector body. The support means in turn
comprise a set of support members in the form of circumferen-
tially spaced wedges engaged in one-to-one relation with re-
spective latch dogs. Link means are preferably providecl
interconnecting the latch dogs and s~pport members to limit
relative radial movement therebetween. The amount of r~lative
radial movementpermitted by the link means may be less than the
total amount of radial movement of the support members duriny
their extension and retraction. Thus, after partial retraction
of the support members, by release means cooperative between
those support members and the drive means, further retraction
of the support members will cause retraction of the latch dogs.
The actuator means is preferably in the form of a longi-
tudinally extendable and retractable drive means, such as an
annular piston, mounted in the connector body. In one preferred
embodiment, this piston has cam surfaces arranged in a gen-
erally stepped configuration engagable with the latch dogs and
support members or successive eY.tension thereof. In a longi-
tudinally extended position, the piston radially abuts the
la~ch dogs and support members to retain them in their radially
extended positions. Lock means may be provlded in association
with the drive means for locking the latter in its longitu-
dinally extended position and thus, in turn, locking the latchdogs and support members in their radially extended positions.
As mentioned above, a release means is preferably also
provided, cooperative between the drive means and support
members, to at least partially radially retract the support
members as the drive means or piston is longitudinally re-
tracted.
Accordingly, it is a principal object of the present
invention to provide an improved wellhead connector.
It is a more general object of the invention to provide an
improved means for conne~ting two tubular bodies in generally
coaxial alignment.
It is another object of the present invention to provide
a wellhead connector having at least partially independently
radially movable latches and support means, the latter, when
extended, wedging with respect to the former and the body on
which they are carrie~.
Still another objèct of the present invention is to
provide means for releasing the support means along with link
means cooperative between the support means and the latch means
for assisting in retraction of the latch means.
Still other objects, features, and a~vantages of the
present invention will be made apparent by the following
detailed description of an exemplary embodiment, the drawings,
and the claims.
--7--
Brief Description of the Drawings
Fig. 1 is a longitudinal cross-sectional view through a
wellhead and wellhead connector in accord with the present
invention, with the latches and the support dogs in their fully
retracted positions.
Fig. 2 is an enlarged partial sectional view through the
appartus of Fig. 1 with the latches fully extended and the
s~pport dogs partially extended.
Fig. ~ is a view similar to Fig. 2 with the latches and
support dogs fully extended and the actuator piston locked in
its extended position.
Fig. 4 is a view similar to that of Figs. 2 and 3 showing
the actuator piston and support dogs partially retracted.
Fig. 5 is a transverse cross-sectional view taken along
the lines 5-5 in Fig. 1.
Fig. 6 is a longitudinal cross-sectional view through a
second embodiment of wellhead connector in accord with the
present invention, with the latch means fully extended.
Fig. 7 is an enlarged partial sectional view of the
ap~dLdlu~ of Fig. 6 with tne support means fully extended.
Fig. 8 is a further enlarged detailed sectional view.
Fig. 9 is a view similar to that of Fig. 8 showing the parts
in another position.
Fig. 10 is a view taken along line 10-10 in Fig. 9.
--8--
Detailed Descri~tion
Fig. 1 shows a typical wellhead 10 and a wellhead con-
nector, generally denoted by the numeral 12, for connection
thereto. Connector 12 may in turn mount a blowout preventor
stack or any other apparatus which is to be ultimately connected
to the wellhead 10. Connector 12, as a whole, is tubular and
is to be connected to wellhead 10 in generally coaxial align-
ment. More specifically, connector 12 includes a tubular main
body comprising an annular outer wall 14 and an annular inner
waii 1~ Inner wall 16 has an integral flange 18 extending
radially o~twardly from its upper end and connected to o~ter
wall 14 by screws 19. The main body further includes a
generally cylindrical cage 20 which is threadedly connected to
a reduced diameter portion 16a of inner wall 16 and extends
downwardly therefrom to form an extension of said inner wall.
The outer wall 14 is radially spaced from inner wall 16 and its
extension 20 so that an annular space is formed therebetween.
An actuator in the form of a longitudinally reciprocable
annular piston 22, to be described more fully below, is mounted
in said annular space.
As may be seen by comparing Figs. 1 and 5, cage 20 has a
plurality of circumferentially spaced windows 24 opening
radially therethrough. The latches for the wellhead connector
are formed by a first set of members, specifically latch dogs
26, each of which is mounted in a respective one of the windows
24 in cage 20. A second set of members, specifically wedges 28,
is provided to form the support means of the device. Each wedge
28 is mounted in a respective one of the windows 24 below the
respective latch dog 26.
Latch dogs 26 have, on their radially inner sides, saw
tooth formationsgenerally denoted by the numeral 30 configured
~o mate with circumferential grooves which define similar saw
tooth formations 32 on the outer diamter of wellhead 10 near its
upper end. It can be seen that, if the latch dogs 26 are
extended radially inwardly so that formations 30 and 32 are
matingly engaged, the wellhead connector will be e~fectively
latched to the wellhead 10. Each support wedge 28 carries a pin
3~ which extends upwardly from the support wedge 28 and into a
slot 36 in the respective latch dog 26 thereabove. Pins 34 and
slots 36 permit limited relative radial movement between the
latch dogs 26 and support wedyes 28 in a manner to be
de~cribeo more fully below. Similarly, each support wedge 28
has a slot 38 receiving a respective pin 40 mounted in cage 20
and extending upwardly into the respective one of the windows
24. Pins 40 and slots 38 permit limited relative radial
movement between support wedges 28 and cage 20 and serve to
retain wedges 28 from becoming completely dislodged from cage
20, dogs 26 in turn being retained with respect to wedges 28 by
pins 34.
Piston 22 includes a cylindrical membex 42 having a
portion 44 of reduced outer diameter, portion 44 being engaged
by an annular flange 46 extending radially inwardly from outer
body wall 14. The inner surface of flange 46 is sealed with
respect to reduced diameter portion 44 of the piston by O-rings
48, and the enlarged diameter portion 50 of the piston member
42 below portion 44 is sealed with respect to wall 14 by O-rings
52. Accordingly, a first piston head is defined by the annular
area of portion 50 between O-rings 48 and O-rings 52. If fluid
pressure is admitted to the area between flange 46 and piston
portion 50 through a passageway, partially shown at 54, the
piston may be urged downwardly. The piston assembly further
comprises a ring 56 fixed to the upper end of member 42 by screws
58. Ring 56 is sealed with respect to member 42 by O-rings 55
and 57. The outer diameter of ring 56 is the same as that of
portion 50 of piston member 42 and is sealed with respect to
outer body wall 14 by O-rings 60. Thus, if fluid pressure is
admitted to the area between flange 46 and the second piston
head formed by ring 56 through passageway 62, the piston
assembly 42, 56 can be urged upwardly.
Fig. 1 shows piston assembly 42, 56 in its uppermost
position, which will be referred to herein as its "longi-
tudinally retracted" position, and the members 26 and 28 in
their radially outermost positions, which will be referred to
herein as their "radially retracted" positions. These are
the positions in which the parts would be disposed as the
wellhead connector is lowered over wellhead 10. Suitable ~uide
--10--
means (not shown) would be provided to coaxially align the
wellhead connector and wellhead. Downward movement would be
stopped by abutment of the lower end of inner body wall 16 with
the ~pper end of wellhead 10 as shown in ~ig. 1. At such point,
the formations 30 and 32 are then in alignment with each other.
To bring these formations into latching engagement, fluid
pressure would be admitted through passageway 54 to lower
piston 22. (While various steps in the latching and unlatching
pro~ess are shown in various figures, it will be helpfull to
also refer to Fig. 1 throughout the description of the operation
of the tool.) The inner s~rface of piston member 42 has a
generally stepped configuration including an uppermost
straight vertical section Ç4. Adjoining the lower end of
section 64 is a downwardly and radially outwardly inclined
section 66. Adjoining the lower end of section 66 is a section
68 which, while it is also downwardly and radially outwardly
inclined, has a much smaller radial component of direction
so that it is more mearly vertical than section 66. Finally,
adjoining the lower end of section 68, is a short section 70
inclined at about the same angle as section 66. As piston 22
is lowered, section 66 of the inner surface of piston member 42
will come into engagement with matingly inclined surfaces 72
formed at the upper outer corners of latch dogs 26.
Accordingly, as piston 22 is further lowered, surfaces 66 and
72 will act as cam surfaces to push latch dogs 26 radially
inwardly. Because pins 34 are disposed at the outer extremities
of recesses 36, wedges 28 will be urged inwardly along with dogs
26. Support wedges 28 have horizontal lower surfaces which
slidingly engage the horizontal surfaces 74 at the bottoms of
windows 2g to slidingly guide the wedges 28, and thus indirectly
the dogs 26, in such radially inward movement.
Fig. 2 shows pertinent portions of the apparatus part way
through the downward stroke of piston 2~, and more
specifically, after cam surface 66 of the piston has mo~ed
downwardly past cam surfaces 72 of latch dogs 26. It can be seen
that, at this point, latch dogs 26 are in substantially their
innermost positions with formations 30 and 32 in latching
engagement. In other words, the generally upwardly facing
surfaces 32a on the saw tooth formations ~f doys 26 and the
generally downwardly facing surfaces 30a on the grooves of the
wellhead have been brought into opposition with each other
whereby they may serve as latching surfaces to prevent upward
S movement of the wellhead connector from the wellhead. However,
even thoughlatch dogs 26 have been moved to substantially their
full radially extended position, the connection has not yet
been tightened longit~dinally since wedges 28 are still in
their radially outer positions with respect to dogs 26.
As previously mentioned, the latching surfaces 30a of
latch dogs 26 face generally upwardly. The generally down-
wardly ~acing underside 7R of each latch dog 26 abuts a
generally upwardly facing surface 80 of the respective support
wedge 28. Opposed surfaces 78 and 80 will be referred to herein
as "support surfaces" since they support dogs 26 or resist
movement thereof longitudinally in a direction whichwould tend
to separate latching surfaces 30a and 32a. Wedges 28 are in
turn supported by their lower surfaces 82 on the upwardly facing
surfaces 74 of windows 24, surfaces 74 and 82 being referred to
herein as "slide surfaces." In accord with the present
invention, after latch dogs 26 have been substantially Eully
extended, support wedges 28 are successively urged further
radially inwardly, wedging between support surfaces 78 of the
latch dogs 26 and slide surfaces 74 of the cage 24. Because the
opposed support surfaces 78 and 80 of the respective latch and
support dogs are inclined radially outwardly and longi-
tudinally upwardly, such further radially inward extension of
wedges 28 will tighten the connection with the wellhead, more
specifically, the engagement between generally longitudinally
facing latch surfaces 30a and 32a, without any substantial
additional radially inward movement of the latch dogs 26.
Accordingly, latch dogs 26 will notdig in~o the relatively soft
metal ofwellhead 10 thereby thwarting the effort to tighten the
connection, as occurs in prior art devices. Rather, during the
tightening portion of the operation of the tool, all sub-
stantial relative radial movement is between supportwedges 28,
on the one hand, and latch dogs 26 and cage 24, on the other,
and all of these parts can be formed of harder metals than
-12-
wellhead 10 and can include surface finishes or treatments
which insure minimum frictlon. Dogs 26 are thus wedged upwardly
into tight engagement with the wellhead.
More particularly, the additional radial extension of
wedges 28 is accomplished by further downward movement of
piston 22. Xeferring again to Fig. 2, after cam surfaces 66 and
72 have mo~ed past each other, surface 70 will come into
engagement with matingly inclined surfaces 76 formed on the
upper outer corners of wedges 28 to cam the latter further
radially inwardly. This accomplishes the wedging type tigh-
tening described above. Then, surface 68 of piston member 42
will come into alignment with the radially outer surfaces 84 of
dogs 28. Surfaces 68 and 84 are matingly inclined, and although
their radial component of direction is very small, they will
accomplish a further slight camming effect on wedges 28 to fully
tighten the connection between the wellhead 10 and the wellhead
connector.
Fig. 3 shows the apparatus with piston ~2, 56 in its fully
extended or lower position, and with members 26 and 28 in their
fully extended or radially inner positions. In this position,
surface 64 of piston member 42 radially abuts the outer side of
latch dogs 26, while surface 68 similarly abuts the radially
outer sides of wedges 28 to retain the dogs and wedges in their
extended positions. Piston 42, 56 can be loc~ed in this
position by a mechanism shown in the unlocked configuration in
Figs. 1 and 2 and in the locked configuration in Fig. 3. The
locking mechanism cooperates with a pair of rods B6 threaded
into ring 56 of the piston assembly and extending longitu-
dinally therefrom thr~ugh respective bushings 88 mounted in the
flange 18 of the main body of the wellhead connector. Each bore
in flange 18 in which a bushing 68 is mounted is larger than the
bushing so that it may also receive an annular piston 90,
surrounding a lower, reduced-outer-diameter portion of the
bushing 88, and a set of dog elements 92 mounted below both
35 bushing 88 and piston 90. Piston 90 and dogs 92 have abutting
downwardly and radially outwardly inclined cam surfaces ~ and
96 respectively. Rod 88 has its outer diameter, in general,
sized for a sliding fit in bushing 88, the inner surfaces of
dogs 92 also sliding against the outer diameter of rod 86.
However, rod 86 has, intermediate its ends, a necked down or
reduced-diameter portion 86a. Rod 86 is further beveled both
above and below necked down portion 86a.
Referring now again to Fig. 3, as the main drive piston 42,
56 moves downwardly, each rod 86 moves therewith until its
necked down portion 86a is in alignment with dog elements 92.
This opens up a space for potential radially inward movement of
dog elements 92. To effect such movement, fluid pressure is
applied to the upper side of piston 90 through passageways (not
shown), and as piston 90 moves downwardly, surfaces 94 and 96
cam dog elements 92 radially inwardly into engagement with
necked down portion 86a of rod 86. Piston 90 then moves in
behind (or radially outwardly of) dog elements 92 to retain them
in that position as shown in Fig. 3. It should be noted that,
in such locking position, the downwardly and radially outwardly
beveled surface on rod 86 below its necked down portion 86a
abuts matingly beveled surfaces 98 on dog elements 92.
When it is desired to release the wellhead connector from
wellhead lO, the locking mechanism is first disengaged. This
is accomplished by applying fluid pressure, via passageways
~not shown~, to urge each piston 90 upwardly thus freeing dog
elements 92 for potential radially outward movement with
respect to rod 86. Fluid pressure is then applied to upper
piston head 56 of the main drive piston through passageway 62.
As piston member 42 moves upwardly, and surfaces 64 and 68
thereof move out of alignment with respective sets of members
26 and 28, the latter are freed for potential retraction. To
ensure such retraction, a release mechanism is provided. This
mechanism includes a sleeve 100 formed integrally with piston
member k2 and extending downwardly therefrom. At the lower end
of sleeve lO0 is an annular flange 102 which extends radially
inwardly terminating in an upturned lip 10~ having an upwardly
and radially inwardly inclined upper surface 106. Each of the
support wedges 28 has a tang 108 extending downwardly from its
outer lower corner and having a surface llO on its underside
inclined to correspond with the inclination of surface 106 on
lip 104.
As piston 42, 56 moves upwardly, surfaces 106 and 108 will
come into engagement with each other and cam the support wedges
28 radially outwardly as shown in Fig. 4. Wedges 28 will first
move outwardly with respect to dogs 26 to the extent permitted
by pins 34 and slots 36. Fig. 4 shows the apparatus at such
point in the retraction process. From that point, further
upwarcl movement of piston 42, 56 and consequent camming action
of surfaces 106 and 110 will cause members 28 and 26 tv move
outwardly ~ointly by virtue of the engagement of pins 34 with
the radially outer extremities of slots 36. Meanwhile, the
beveled surfaces on rods 88 below their necked down portions 86a
will have cammed dog elements 92 radially outwardly, i.e. back
to the position shown in Figs. 1 and 2, so that, ultimately, the
entire apparatus returns to its fully retracted position shown
in Fig. 1. The locking mechanism is provided with a manual
override in the form of pins 112 connected to piston 90 and
slidably extending outwardly through bushing 88 so that their
heads can be engaged to force piston 90 upwardly mechanically.
Compression springs 114 are provided between cage 20 and
support wedges 28 to aid them in returning to their radially
retracted positions.
Figs. 6-10 show a second embodiment of wellhead connector
according to the present invention. The connector is adapted
for connection to a wellhead 200 whose upper profile includes
a radially outwardly extending flange 202, the underside of
which defines a generally downwardly facing annular latching
surface 204. The wellhead connector includes a generally
tubular main body which comprises a generally cylindrical inner
portion 206 having at its lower end a radially outwardly
extending flange 208 adapted to abut and form a mirror image of
flange 202 ofthe wellhead 200. Spaced upwardly from flange 208
is another annular radially outwardly extending flange 210 to
which is bolted the outer portion of the main body of the
connector. More specifically, said outer portion includes an
upper annular plate 212 bolted to flange 210 by bolts 214 and
extending ra~ially outwardly, a cylindrical outer wall 216
welded or otherwise rigidly affixed to the outer extremity of
plate 212 and extending downwardly therefrom, and a lower
annular s~pport plate 220 secured by screws 218 to lower end of
wall 216 and extending inwardly therefrom. As shown, the o~ter
portion 212, 216, 220 of the connector main body is generally
C-shaped in cross sections, and an annular space 222 is defined
between the inner and outer portions oE the connector main body.
An annular piston and cylinder assembly 224 is mounted on
the upper side of plate 220. Its annular piston rod 226 extends
~pwardly and has an annular cam member 228 rigidly secured to
its upper end. Cam member 228 includes a generally horizontal
10flange 228a secured to piston rod 226, and a cam proper 228b
depending downwardly from the radially inner extremity of
flange 228a. The piston and cylinder assembly 224 together with
the attached cam ring 228 form the actuator means for the
connector.
15Fig. 6 shows the actuator means in an intermediate posi-
tion between the ends of its stroke. In its uppermost position
(not shown), the upper end of cam 228b abuts radially outwardly
projecting lugs 230a integrally formed on the upper ends of a
plurality of dogs 230 circumferentially spaced about annular
space 222. This causes the lower ends of dogs 230 to pivot
radially outwardly, in a manner well known in the art, so that
their lower ends can clear flange 202 of wellhea~ 200 as the
connector is being run in.
Each of the dogs 230 has, on its radially inner side, a
recess 232 which generally opposes flan~3es 202 and 208. ~arried
within each recess 232 are a pair of bearing members 234 and
236, mounted respectively on the upper and lower end surfaces
of the recess 232. As best shown in Figs. 8 and 10, bearing
member 234 has a slot 238 extendin~ generally vertically
therethrough, slot 238 being further enlarged in both length
and width at 238a. One end of the enlarged area 238a communi-
cates with a bore 240 extending parallel to slot 238, but
separated therefrom, and permits access to bore 240 whereby a
shear pin 242 can be implaced into bore 240 and an opposed
recess in dog 230. Thus, pin 242 initially holds bearing member
234 in a desired position with respect to dog 230, more
specifically, a position in which bearing member 234 projects
slightly radially inwardly from recess 232. Slot 238 and its
-16-
enlarged end portion 238a likewise permit a screw 244 to have
its end threaded into a tapped bore 246 in the upper surface of
recess 232. The remainder of the shank of screw 244 is
slideably received in the smaller portion of slot 238, while the
head of screw 244 is received in the enlarged portion 238a of
the slot and ab~ts the shoulder formed between the smaller and
enlarged portions of the slot. Thus, the head of screw 244
retains bearing member 244 from being completely separated from
dog 230 after pin 242 is sheared. Referring again to Fig. 6,
bearing member 236 is similarly secured to the lower surface of
recess 232 by shear pin 246 and screw 248.
While the space between flanges 202 and 208 has been
exaggerated in Fig. 6 for purposes of illustration, it is
understood in the art that, after the wellhead connector has
been emplaced on the wellhead 200, the two flanges are not
tightly urged together. The under surface 204 of flange 202 is
inclined radially outwardly and upwardly, and serves as a
latching surface in a manner to be described more fully below.
The oppositely directed upper surface of flange 208 is inclined
radially outwardly and downwardly in mirror image fashion. As
actuator 224, 228 is urged downwardly, the radially outwardly
and downwardly inclined inner surface of cam 228b engages ~he
correspondingly inclined outer surfaces of dogs 230 to pivot
the dogs radially inwardly, bringing recesses 232 into recei-
ving relation to flanges 202 and 208. Bearing members 234 and
236 will move inwardly along with dogs 230 until the radially
inner ends of the bearing members come into abutment with the
wellhead 200 and inner connector portion 206 adjacent their
respective flanges 202 and 208. Figs. 6 and ~ show the
apparatus in such position. It should be noted that the sizing
of recesses 232 and bearing members 234 and 236 is such as to
permit the aforementioned radially inward movement to occur
without resistence from either the main body of the connector
or the wellhead.
As the actuator 224, 228 continues to move downwardly from
the position of Fig. 6 to that of Fig. 7, it exerts further
radial force on dogs 230, shearing pins 242 and 246, and thereby
permitting dogs 230 to be extended further radially inwardly
with respect to be~ring members 234 and 236. The upper and
lower surfaces of bearing members 234, as well as the adjacent
upper surfaces of recesses 32 are inclined in the same general
direction as the adjacent upper surface of flange 208. Simi-
larly, the upper and lower surfaces of bearing members 236, andthe lower surfaces of recesses 232 are inclined in the same
general direction as the lower or latching surfaces 204 of
flange 202. Thus, as dogs 230 move radially inwardly with
respect to the flanges 202 and 208 and the abutting bearing
members 234 and 236, the dogs will act as wedges to draw flanges
202 and 208 into tight longitudinal engagement as shown in Fig.
7.
During the above described movement, it can be seen that
bearing members 236 serve as the latch members, their upper
surfaces serving as the latch surfaces for abutment with latch
surface 204 of flange 202. The lower surfaces of bearing
members 236 and the abutting lower surfaces of recesses 232
serve as the support surfaces which prevent separation of the
latch surfaces. The upper bearing members 234 aid the movement
of dogs 230. However, it can be understood that the upper
bearing members could be omitted, and recess 232 sized for its
upper surface to directly engage flange 208. Where upper
bearing members 204 are employed, once they come into abutment
with the connector body portion 206 above flange 208, they
effectively act as a part of the main body of the connector and
provide a bearing surface thereon for dogs 230. In any event,
it can be seen that, with dogs 230 extended in to their inner
positions, the upper surfaces of recesses 232 and flange 208
oppose each other, and will effectively limit downward movement
of dogs 230 relative to the main body of the connector either
by direct abutment, or via the bearing members 234 interposed
therebetween.
To unlatch and retrieve the wellhead connector, actuator
means 224, 228 is urged upwardly. When the upper surface of cam
228b reaches the lugs 230a of dogs 230, continued upward
movement of the actuator means will pivot the lower ends of dogs
230 radially outwardly, carrying bearing members 234 and 236
with them via screws 244 and 248. When the lower portions of
dogs 230, and the attached bearing members 236 have cleared
flanged 202, the connector can be retrieved. It should be
understood that vario~s other features, such as a means for
locking the apparatus in latched position, could be included in
the simplified version of the connector illustrated in Figs. 6-
10 .
The above represent only two exemplary embodiments of the
invention, and numerous modifications will suggest themselves
to those of skill in the art. By way of example only, in the
embodiments described and shown above, the latch means and
support means first move radially inwardly jointly, followed by
further radially inward movement of the support means. In other
embodiments, the latches might first move radially inwardly
independently oE the support means followed by move~ent of the
support means themselves. As used herein, the term "successive
movement" will refer to either of these two patterns of move-
ment, as well as to any other pattern in which movement by the
latch means, with or without the support means, is followed by
movement of the support means independently of the latch means.
Other modifications might involve the form of the various
parts of the invention. For example, in the embodiments shown,
the support means is in the form of a plurality of circum-
ferentially spaced members. In other embodiments, the support
means might be a single member, such as a split ring. Still
other modifications might involve the means for releasing the
support means and/or the latch means from their extended
positions. Even further modifications will suggest themselves
to those of skill in the art. Accordingly, it is intended that
the scope of the present invention be limited only by the claims
which follow.
