Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
1156214
This is a division of commonly assigned Canadian
Patent Appli,cation Sexial No. 374,317 ~iled Maxch 3i, 1981.
- Technica} Field
This invention relates generally to a bowl and slips
assembly such as may be used in supporting tubing in a well
snd, more'specifically, relates to the construction o~ the
assembly in providing for the use of removable slip inserts.
Background Art
In the petroleum industry, a bowl and slips assembly,
typically referred to as a spider and slips, comprises a sup-
10 port or bowl having a central opening through which tubing
~, may extend downwardly into an oil well. The sides of the
opening are tapered inwardly upon progressing downwardly
through the bowl so the opening is generally of an inverted
frustoconical shape. To support the tubing upwardly within
15 the bowl, a series of bodies in the form of frustoconicalsegments are telescoped into the opening, In one form of
assembly, there are four such slip bodies dividing the open-
ing into quadrants. Together, the slip bodies define a
cylindrical passage through the central opening and the pas-
20 sage is particularly sized to receive the tubing for supportby the assembly. Carried on the inside sur$aces of the slip
bodies for gripping against the outside of the tubing are
removable inserts having vertically spaced teeth which
typically are configured for one-way grippin~ to keep tubing
2S from sliding downwardly in the well.
In service use, pairs of the slip bodies may be sup-
ported in retracted positions spaced outwardly from opposite
sides of the opening to allow tubing to be lowered into the
well. When it is,desired to move the slip bodies and inserts
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into the opening to grip the tubing, the bodies are moved into
set positions with the teeth gripping a~ainst the tu~ing.
Sometimes gripping occurs before downw~rd movement of tubing
being lowered into the well is halted and, as a result, high
instantaneous forces are generated in the assembly~ It will
be appreciated that these forces of dynamic loading applied
to the inserts and slip bodies can be quite high, particularly
when the assembly is used to support the weight of thousands
of feet of tubing.
10 Disclosure of Invention
... ..
In general, the present invention contemplates a
bowl and slips assembly of the foregoing general character
which is easier to use and which has a longer service life
than prior similar bowl and slips assembliesO In this re-
15 spect, the present invention provides connections between theslip bodies and their inserts which are constructed in a
particularly unique fashion so that wear and metal fatigue
associated with repeated loading in tension during in service
use is concentrated in the easily replaceable inserts rather
! 20 than in other parts of the assembly such as the slip bodies.
Primarily, the present invention resides in the con-
struction of the bowl and slips assembly to include a novel
cantilever connection for hanging each of the inserts from
their respective slip bodies so the reaction forces throug~
25 the assembly when supporting the tubing places the slip bo~ies
in compression. Specifically, the inserts arè hang-suppor~ed
from top surfaces of the slip bodies and, between adjacent
pairs of slip bodies, these top surfaces are spaced vertically
from each other to advantageously position horizontally
30 parallel gripping teeth of identical inserts in vertically
offset patterns to avoid creating an unbxo~en line of force
concentration completely around the tu~ing supported by the
assembly.
The invention also resides in the novel manner of
35 mounting the inserts in the slip bodies for easy removal ana
replacement and in the provision of a safety ledge for keeping
the inserts from dropping into the well in the event the
cantilever connection should fail
1156214
The invention accordiny to the ~arent applica~on may be
considered as providing a bowl and sl~ps asse~ly ~or support-
inq tubing upwardly within a well, comprisin~: a support ~owl
with a downwardly tapered opening therethrough for the tubing
to extend into the well, a first pair of sli~p ~odies pivotally
mounted on the bo~1 adjacent one side of the openîng for
movement between a retracted position spaced clear of ~he.
opening and a set position within the. opening, a second similar
pair of slip bodies pivotally mounted on thed support bowl on
the opposite side of the opening for similar movement between
retracted and set positions relative to thël opening, fluid
pressure actuating mechanism mounted on the.. support bowl and
connected ~etween thed first and second pairs of slip bodies
for moving thë.. pairfi of slip bodies simultaneously between
their retracted and set positions, each of the.. slip bodie~s
having an insert connected thereto and carried thereby for
gripping against the outside surface of the tubing to support
the latter upwardly in the well, and a cantilever connection
between the inserts and their associated slip bodies, the;l
connections supportively hanging each of the.. inserts in a
loaa bearîng position from their respective slip bodies so
the weight of the tubing supported by the assembly piaces the;l
slip bodies in compression.
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1156214
Statement of Invent;.on
On the other hand the invention according to
this divisional application may be considered as providing
a bowl and slips assembly having a plurality of tapered
slip bodies with associated gripping inserts angularly
spaced about the central axis of and mounted on a support
bowl for movement between retracted and set positions with
respect to a tapered opening in the bowl for the inserts
to grip against the outside surface of tubing to support
the latter upwardly in a well, the improvement in the
assembly comprising a cantilever connection hang support-
ing`each of the inserts from their respective slip bodies`
in a load bearing position so the reaction of forces through
the assembly when supporting tubing places thé slip bodies
in compression, each of the connections including a top
surface on the 51ip bodies and each of the inserts includ-
ing an inner gripping surface and a lip projecting outwardly
therefrom with the lips being in overlapping abutting engage-
ment with the top surfaces of the slip bodies in the load
bearing position, and with the inserts being substantially
identical to each othar and the inner gripping surfaces
thereof ~eing compri~ed of a plurality of vertiaally spaced,
substantially parallel teeth, and the top surfaae of one slip
body being offset vertiaally from the top surface of an adja,
cent slip body.
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These and other objects and adv~ntages of the
present invention will become more apparent from the follow-
ing description when ~aken in conjunction with the accompanying
drawings.
BRIEF DESCRIPTION OF DR~WINGS
Fig. l is a front view of a bowl and slips assembly
embodying the novel features of the present invention.
Fig. 2 i5 a back view of the bowl and slips assembly
of Fig. 1.
Fig. 3 is a plan view of the assembly shown in Fig. 1.
Fig. 4, on the same sheet as Fig. 1, is a view similar
to Fig. 2 but showing parts of the assembly in moved positions.
Fig. S is a perspective view showing specific parts
of the assembly in exploded relationship to each other with
other parts of the assembly-omitted for clarity.
Fig. 6 is a partial, cross-sectional and elevational
view taken substantially along line 6-6 of Fig. 3.
Fig. 7 is an enlarged, fragmentary view taken sub-
stantially along line 7-7 of Fig. 3.
~igs. 8 and 9 are enlarged perspective views of
different sides of a slip body insert utilized in the exem-
plary bowl and slips assembly.
BEST MODE OF CARRYING OUT THE INVENTION
As shown in the drawings for purposes of illustration,
the present invention is embodied in a bowl and slips assembly
15 such as is used in the petroleum industry to support tubing
(not shown) in an oil or gas well. Herein, the assembly
comprises the support bowl 16 with a bottom flan~e 17
. 1156214
~see Figs. 1 and 6) for attachincJ the bow] at the well.
head. When removed, a gate 19 in one side of the bowl
connects tubing to be loaded sideways into axial alignment
with the well bore. In place, the inner surface of the gate
is tapered in conformity with the remaining portion of the
bowl to define a central opening 20 through which the tubing
may be lowered into the well. The gate is held against
radial movement relative to a central axis 21 of the opening
by interfitting groove 23 and ridge 24 connections formed in
opposite ends of the gate (see Fig. 3) and the adjacent sides
.
.: . .
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of a gate opening 25 in the bowl. Additionally~ a retaining
pin 26 telescoped horizontally through the bowl and the gate
serves to support the gate against vertical movement once in
place.
The central opening 20 of the bowl 16 is generally
- of an inverted, frustoconical shape and thus tapers inwardly
upon progressing downwardly through the bowl. To support the
tubing within the bowl, a series of similarly tapered slip
bodies 27a and 27b and 28a and 28b fit within the opening and
10 include inner gripping surfaces or teeth 29 particularly
adapted to bite agaînst the outside of the tubing within the
bowl and support such tu~ing against downward movement into
the well. -Herein, teeth 29 are formed on the inside surface
of removable inserts 30 carried by the slip bodies and are
15 shaped for one-way gripping to keep the tubing from sliding
downwaraly in the well. Because of the ~edge effect of the
slip bodies in the tapered opening, downward move~ent of the
tubing produces an almost instantaneous gripping of the tubing
~ by the teeth 29.
;~ 20 More particularly, as shown in ~ig. 3, the slip
bodies are connected in pairs 27a, 27b and 28a, 28b on carrier
arms 31 and 33, respectively, which are disposed on opposite
sides of the bowl 16 for movement between set positions with
the slips disposea within the opening 20 and retracted posi-
25 tîons with the slips pivoted upwardly and outwardly of the
opening as shown specifically in Fig. 4. ~erein, a hydraulic
actuating mechanism 34-is utilized to pivot the carrier arms
31 and 33 in lifting the slip bodies from their set positio~s
and into their retracted positions. As shown in Figs. 3 and
30 6, such mechanism includes a hydraulic cylinder 35 supported
on one side o the bowl 16 with a rod end 36 of the c~linder
facing upwardly. A rod 37 connected to a piston 3~ ~Fig. 6~
in the cylinder projects upwardly therefrom to connect pivo -
ally with the carrier arm 31 intermediate inner and outer erds
35 40 and 41 thereof. The outer end of the carrier arm 31 is
fixed to a pivot sha~t 43 rotata~ly supported within journals
44 and 45 (see Fig. 3) connected to the bowl. Adjacent the
backside of the bowl, a lever arm 46 is fixed by one end to
the shaft 43 and an opposite end o the lever arm is pivota~ly
40 connected to one end of an elongated link 47 extending alons
~156214
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the back side of the bowl. At an opposite end of the link 47,
a second lever arm 49 is fixed to a second pivot shaft 50
which is mounted on the bowl to connect with the arm 33 in a
fashion similar to that of the shaft 43 and carrier arm 31.
5 With this construction, when hydraulic fluid through a line
51 enters the bottom of the cylinder 35~ the piston 39 is
forced upwardly exhausting fluid above the cylinder to a line
53 and pivoting the carrier arm 31 and shaft 43 in a counter-
: clockwise direction as viewed in Fig. 6 while at the same
10 time shifting the link 47 to the left thereby pivoting theshaft S0 clockwise and lifting both pairs of 51ip bodies 27
and 28 from the bowl simultaneously. Movement-of the slip
bodies from their retracted positions into their set positions
is accomplished merely by reversing the application of pres-
lS sure fluid so as to flow into the cylinder through the line 53and out through line 51.
; In moving the pairs of slip bodies 27 and 28 between
their set and retracted positions, interference with the tub-
ing disposed in the well is avoided by virtue of a lost motion
20 connection 52 between the carrier arms 31 and 33 and the slip
bodies. One such connection 52 is shown in Fig. 6 and includes
a slightly elongated slot 54 formed in the inner end 40 of - -
the carrier arm 31 to receive a pin 55 which connects with
upright brackets or ears 56 (see also Figs. 3 and 5) extending
25 from the slip bodies 27a and 27b. A like construction mounts
the slip bodies 28a and 28b on the carrier arm 33. Advanta-
geously, this construction allows the slip bodies to remain in
a more nearly vertical orientation relative to the central
axis 21 o the opening 20 (rather than cocking angularly with
30 respect to vertical) as the carrier arms 31 and 33 are pivoted
by allowing the pins 55 to traverse horizontally along the
slots 54. Thus, interference between bottom inner edges 57
~see Figs. 5 and 6) of the slip bodies 27 and 28 and the outer
surface of the tubing is avoided. -
In service use, it is not unusual for the slip
bodies 27 and 28 to ~e moved into their set positions for
supporting tubîng even though downward movement of the tubing
in the well has not been halted completely. Accordingly, it
will be appreciated that high instantaneous forces are
.. . . ..
` 1156214
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genexated in the assembly lS resulting both from the dead
weight of the tubing and its dynamic loading as tb~ wei~ht
impacts on the assembly when the slips bite against and are
wedged in the bowl 16. As a result, substantial wear and
5 even breakage of parts of the assembly may occur from re-
peated impact, loading and relative sliding of the tubing on
parts of the assembly.
'- In accordance with the primary aim of the present
invention, the bowl and slips assembly 15 is constructed in a
10 novel fashion for easier in service use and'''longer useful
service life through the provision of a unique connection 5
between each of the 51ip bodies 27 and 28 and their associated
inserts 30. Particularly, *hese connections are such that
wear and metal fatigue associated with repeated loading is
~` 15 concentrated in the inserts and yet allows for easy removal
and replacement of the inserts. For these purposes, the con-
nections are cantilevered for hanging the inserts from their
~' respective slip bodies so the reaction of forces through the
'~"'i assembly'when supporting tubing places the slip bodies in com-~- 20 pression. By virtue of constructing the assembly to utilize
cantilever connections in this fashion, the useful service
life of each of the slip bodies is incxeased substantially.
' Moreover, the cantilever connections are particularly suited
for easy replacement of inserts as may be necessary from time
25 to time.
As shown in Figs. 6 and 7, the connections 59 uti-
lized herein are substantially the same for each of the in-
serts 30 and their associated slip bodies 27 and 28. Accord-
' ingly, only one of the connections will be described in detail,
30 it being understood that such description applies equally tothe connections for all of the inserts and their associated
slip bodies. In the present instance, the connection 59 is of
a cantilever type and includes a-lip 60 formed integrally with '
the insert 3Q (see Figs. 8 and 9) and projecting outwardly
35 therefrom to overlap a top surface 61 of an associated slip
body 27a. Specifically, the insert is formed substantially
as a lon~itudinal quarter segment of a tubular member and
includes an arcuate inner surface 63 upon which the teeth 29
axe ormed and w~ose central axis extends colinearly with the
1 156214
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central axis 21 o the opening 2a when the insert and its
associated slip body are located in their set positions.
Opposite sides 64 and 65 (see Fig. 31 of the insert extend in
a generally radial direction outwardly from the inner surface
63 to intersect at generally right angles with symmetrical
longitudinal flats 66 ~see Fig. 9) which define laterally
spaced portions of the back side of the insert. Extending
between these two ~lats is a planar outer surface 67. Pref-
erably, the lip is formed integrally with the upper end of
10 the planar outer surface 67 and includes a downwardly facing
lower lip surface 69 (see Figs. 8 and 9) extending outwardly
in a generally perpendicular direction from the outer surface
67. Opposite end walls 70 of the lip intersect at substan-
tially right angles with respect to the 1ats 66 and an out-
15 ward wall 71 (see Fig. 9) extends in a generally tangentialdirection relative to the inner surface between the two end
walls 70. An upper side 73 of the lip is coplanar with the
top surface of the insert and thus is identified by the same
reference number. ~ormed through the upper side of the lip
20 and the top surface of the insert îs a generally rectangular
groove 74 extending in a generally radial direction relative
to the central axis of the insert~ The insert 30 is hang-
supported on the slip body 27a with the lower surface 6~ of
the lip 60 overlapping and abutting the top surface 61 of the
25 body. Supporting the insert against upward movement on the
body is a keeper 7S (see ~ig. 3) which in the present instance
is in the form of a cotter pin extending from within the
groove 74 and through the hole 76 (see Fig. 5) in an upright
lug 77 which is integral}y formed with the top surface 61.
Additionally, the insert 30 is captivated on the
slip body 27a by a telescoping interfit within slot means
formed within the slip body. Herein, the slot means is of a
configuration corresponding to the configuration of the in-
sert so as to define a generally dovetail like interfit limit-
35 ing the insert against movement both in a generally inward
radial direction and in a sideways or circumferential direction
relative to the slip body. Specifically, the slot means com-
prises a recess 79 (s~e ~ig. 5) which is formed within an
inner surface 80 of the slip body 27a and is defined by an
`` ll5S214
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open top, a closed side 81, and an open side. The closed
side extends edgewise in a generally xadial direction for
abutting engagement with the radial side 65 of the insert.
To captivate the other side of the inserk within the recess,
5 an integral projection 83 Ssee Fi~s. 5 and 81 extends up-
wardly from the top surface 61 of the slip body adjacent the
open side thereof and abuts the e~d wall 70 of the lip 60 with
an upright sidewall 82 (see ~ig. 3) to prevent the insert from
moving radially inward when the lip is seated against the top
10 surface of the slip body. The projection also serves to limit
sideways movement of the insert in a direction circumferential-
ly toward the open side of the recess 79. Additionally, such
sideways movement is prevented by an adjacent insert 30 in
the adjacent slip body 27b. Herein, the latter bod~ ~7b is a
15 mirrow image of the slip body 27a so the open sides of the
recesses 79 face each other and thus sides 64 and 65 of adja-
- cent inserts are juxtaposed relative to each other.
As a safety feature for supporting the insert 30
- against dropping into the well in the event of breakage during
20 in service use, an added feature of the present invention
; resides in the provision of a stop 84 for blocking downward
movement of the insert in the recess 79. Herein, the stop is
in the form of a ledge 84 extending radially inward from the
back side of the recess. Preferably, the ledge is spaced
25 ~elo~ the top surface 61 of the slip body 27a a distance
greater than the length of the insert extending beneath the
lower surface 69 of the lip 60. ~s a result, when the insert
30 is positioned within the recess of the slip body 27a, the
lower end 88 (see Figs. 7 and 9) of the insert is spaced up-
30 wardly of the ledge 84.
Of further advantage herein, the inserts 30 are con-
templated as being of identical construction with their teeth
29 extending horizontally and parallel to each other. Thus in
addition to manufacturing simplicity, for example, in any set
35 of four inserts 30, the positions of the inserts in the slip
bodies 27 and 28 are fully interchangeable.
To avoid creating lines of stress concentration
around tubing from the teeth 29 of identical inserts 30 biting
into the sides of the tubing, the present invention further
1 156214
_g
comtemplates vertically offsetting the horizontal pattern of
teeth in adjacent inserts to grip the tubing at vertically
spaced positions~ For this purpose, one of the slip bodies
27a, 28a in each pair includes an upper shoulder 85 formed in
the top surface 61 of the body to a vertical height e~ual to
one-half the distance between two adjacent teeth 29 of the
insert. Herein, the shoulder 85 is formed integrally with
the top of the slip body and along the inner surface 80 there-
of or supportive engagement with the lower surface 69 of the
10 insert 30. Accordingly, when all of the inserts are mounted
on their respective slip bodies so the teeth 29 of adjacent
inserts define a central passage 86 (see ~ig 3) through which
the tubing extends into the well, the teeth are positioned
bite in and support the tubing in such a way as to keep from
15 creating a continuous line of stress concentration around the
tubing~ ` -
- ~ To keep the slip bodies 27 and 28 from wedging too
tightly together when in their set positions without tubing
in the passage 86, facing side ends 87 and 89 of the slip
! . 20 bodies 27a and 28a opposite the gate 19 (see Fig. 3) include
spacers 90~ Specifically herein, two of the spacèrs 90 are
formed integrally on the side end wall 87 and are positioned
vertically thereon for abutting engagement with two spacers on
the side end wall 89 of the adjacent slip body 28a when the
25 bodies 27a and 28a are lowered in the bowl 16. With tubing
extending through the bowl, however, the thickness of the
spacers on the adjacent bodies 27a and 28a is such that the
spacers are held apart by engagement of the teeth 29 with the
tubing.
In view of the foregoing, it will be appreciated
that the present invention brings to the art a novel bowl and
slips assembly 15 which by virtue of the unique interfitting
relationship of the slip bodies 27 and 28 and their associated
inserts 30 and the novel manner of hang-supporting the inserts
35 on the slip bodies serves to increase the useful service life
of the slip bodies and to allow easy replacement of the in-
serts either for reasons of:wear or to accommodate tubing of
different sizes. Advantageously, the cantilevered hanging
support of the inserts on the slip bodies 27 and 28 is such
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as to concentrate wear and metal fati~ue in the easily re-
placeable inserts while subjecting the slip bodies primarily
to the less harsh compressive forces of loading as compared
to tensile loading forces. Replacement of the inYerts may be
accomplished by simply and ~uickly a~tuating t~e hydraulic
mechanism 34 to retract the slips, removing the cotter pins
75, and sliding the inserts to be removed out of the slip
bodies. Thereafter, the replacement inserts may be slid into
the open recesses 79 and the cotter pins 75 replaced to com-
10 plete locking the inserts on the slip bodies. Reverse actua-
tion of the hydraulic mechanism 34 then positions the slip
bodies and inserts in the bowl 16 for gripping and supporting
tubing vertically within the well.
.:
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