Note: Descriptions are shown in the official language in which they were submitted.
10~37~62
Background of the Invention
.
This invention relates to improved slip assemblies for
supporting a well pipe in a rotary table.
Each time that a length of pipe is added to or removed
from a drill string, the string must be temporarily supported by
slips positioned within a tapered slip bowl structure in a rotary
table. After the desired length of pipe has been added or removed,
the slips are released to permit vertical movement of the string.
On occasions when the entire string must be removed from the well,
as for replacement of a bit or for other similar purposes, the
necessity for repeated movement of the slips into and out of active
position in first successively breaking a large number of connection s
in the string as it is removed from the well, and then remaking
these connections when the string is again lowered into the well,
results in the expenditure of a great deal of time and effort
just in slip handling. Where the slips are handled entirely
manually, their usually very substantial weight renders it rather
1. 1
1ai87~L~i2
difficult for the workmen to lift the slips into and out of the
bowl, and there is also an ever present danger of injury in such
2 handling of the slips.
3 In an attempt to overcome these difficulties, various
4 types of power slip arrangements have been proposed in the past,
in which a power operated unit has been employed to suspend the
6 slips above the slip bowl, and in some way utilize power for
effecting at least a portion of the slip movement. For example,
8 such power slip arrangements have been shown in U.S.A. Patents
9 Nos. 2,939,683; 3,210,821; 3,270,389; 3,457,605; 3,961,399;
2,570,039 and 2,641,816. Some of these have been effective in
11 operation, and have seen substantial use, but many drilling
12 companies have continued to use manual slips because of the high
13 cost of power slip units, and because most power slip units
require permanent attachment of a support post or other structure
to the rig floor at the side of the rotary table. Space is at
16 a premium on the rig floor, and many drillers hesitate to
17 occupy a portion of that space permanently by equipment which
18 during much of the time will not be in use and r.lay interfere
19 with other operations.
UoS~A~ Patent No. 2,607,098 shows a slip arrangement
21 in which a plurality of slips are supported by a slip bowl
22 structure for relative upward and downward movement, and can
23 be releasably supported in an upper inactive position. U.S.A.
24 Patent No. 2,340,597 shows a device in which an actuating
25 mechanism manually operable from a side of the well pipe can
26 move a slip carrier upwardly and downwardly relative to a slip
27 bowl. U.S.A. Patents Nos. 2,151,208; 2,245,592 and 3,742,562
28 show well pipe supporting 'spiders', which include vertically
29 movablP slips, but which are not capable of rotating with the
pipe as is desirable in a rotary table arrangement of the type
31 with which the present invention is concerned. The first of
~2 these three patents, U.S.A. Patent No. 2,151,208 shows a spider
VB body haviny slips which are actuable uL~ ly and do~ly ky a pivot~
Il 1087162
590-59
1 lever, with a spring urging the slips downwardly to their active
2 position and a latch being operable to hold the lever in its
3 retracted condition.
Summary of the Invention
7 The present invention provides a unique slip assembly~
8 adapted to be supported by and turn with a rotary table, and
9 which is constructed to greatly facilitate and simplify handling
of slips as compared with a completely manual operation, and at
11 the same time avoids the disadvantages of a powered arrangement.
12 The assembly may be left in position on the rotary table during
13 an entire 'round trip' of the string out of and then back into
14 the pipe, and can be quickly and easily actuated between pipe
supporting and pipe releasing positions when each connection is
16 to be made or bro~en. When the slips are in their inactive
17 positions, they are far enough from the axis of the pipe to permit
18 the enlarged tooljointsto pass through the slip assembly without
19 any difficulty. In addition, the assembly does not require
20 mounting of a support post or other structure to the rig floor,
21 but leaves the entire floor area uncluttered insofar as the slip
22 assembly is concerned. The simplicity of the arrangement allows
23 it to be manufactured and sold at a very low cost as compared with
24 power type slip handling equipment.
In a unit embodying the invention, the slips are sup-
26 ported by a carrier structure which is mounted to the slip bowl
27 structure for upward and downward relative movement, and which
28 can be releasably retained by latch means in a lower active pipe
29 gripping position of the slips. In conjunction with the latch
~0 means, the device includes yielding means which urge the carrier
31 structure and slips upwardly and act to return them to an upper
32 retracted position when the latch means are released. The
,ll I
1~87~62 590 59
1 yielding means desirably include one or more springs, preferably a
2 plurality of circularly spaced coil springs acting upwardly against
3 the carrier structure and downwardly against the slip bowl structur~ .
4 These springs may be located within a plurality of mounting post
assemblies which support the carrier structure for its upward and
6 downward movement.
7 The latch means preferably include a latch part which is
pivotally connected to the slip bowl structure and is engageable
9 with a shoulder formed on the carrier structure when the latter is
10 in its lower active position. The carrier structure may be con-
11 structed to have a portion or portions on which one or more workmen
12 may stand, so that the carrier structure and slips may be actuated
13 downwardly against the spring force by the weight of the workmen.
14 For this purpose, the carrier structure may have an outer ring por-¦
15 tion e~.tending about the pipe, which desirably has an interruption
16 at one location, with the latch part being positioned in this
17 interruption and adapted to be released by downward actuation.
18 .
19 Brief Description of the Drawings
The above and other features and objects of the invention
21 will be better understood from the following detailed description
22 of the typical embodiment illustrated in the accompanying drawings,
23 in which:
24 Fig. 1 is a perspective view of a slip assembly constructe
25 in accordance with the invention, with an indication in broken line
26 of the manner in which the two halves of the device may be
27 separated for placement about a drill pipe;
28 Fig. 2 is an enlarged top plan view of the Fig. 1 device;
29 Fig. 3 is a vertical section taken on line 3-3 of Fig. 2,
and showing the device positioned within a conventional master
31 bushing in a rotary table;
32~ ig. 4 is a fragmenta~y vertical section taken on line
4.
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I~ / - !
" _l `
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1 4-4 of Fig. 2;
2 Eig. 5 is a fragmentary sectional view
3 taken on line 5-5 of Fig. 2, and showing the slips latched in
4 their lower active positions; and
Fig. 6 is a fragmentary horizontal section
6 taken on line 6-6 of Fig. 3.
8 Description of the Preferred Embodiment
1~ Fig. 1 illustrates generally at 10 a slip assembly
11 embodying the present invention, shown positioned above an opening
12 11 in a conventional well drilling master bushing 12 positioned
13 within an opening 13 in a rotary table 14 which turns about the
14 vertical axis 15 of a well. The well pipe is illustrated at 16.
In use, the slip assembly 10 is moved downwardly from the position
16 illustrated in Fig. 1 to a position in which a lower slip bowl
17 structure or portion 17 of assembly 10 is received and supported
18 within opening 11 in the master bushing. Fig. 3 illustrates the
19 assembly in that active position within the master bushing
20 and rotary table.
21 Mounted movably to the slip bowl structure 17 is an
22 upper slip carrier or top plate 18, from which a plurality of
23 (desirably four) slips 19 are suspended, for upward and downward
24 movement with the carrier and relative to slip bowl structure 17.
The carrier is guided for this movement by four spaced vertical
26 guide assemblies 20, each containing a coil spring 21 which
27 yieldingly urges carrier 18 and the slips upwardly to their inactiv~ !
28 positions of Figs. 1 and 3. The carrier and slips can be releasabl~ ,
29 retained in lowered active positions (Fig. 5) by a latch element
~0 22.
31 As seen in Fig. 3, the conventional master bushing 12
32 may have an upper externally square portion 23 received in rotary
1~8716Z 590 59
1 driving relation within an upper internally square portion 24 of
2 the recess 13 in the rotary table 14, with a reduced diameter
3 circular portion 25 of the master bushing heing received within
4 a reduced diameter cylindrical bore 26 in the rotary table, to
5 support the m~ster bushing from the rotary table by horizontal shoulders 27.
6 The slip bowl structure 17 of the present device may be formed of
7 two similar semi-circular sections or halves 28 and 29, meeting in
8 a vertical plane 33 (Fig. 3). Externally, these semi-circular sections
9 28 and 29 have upper enlarged diameter essentially cylindrical
10 portions 31 received within an upper enlarged diameter cylindrical
11 portion 32 of the opening 11 through the master bushing, with
12 reduced diameter complementary external cylindrical surfaces 33
13 on the slip bowl segments 28 and 29 being received and confined
14 within a lower reduced cylindrical portion 34 of the master bushing
15 so that the slip bowl assembly is effectively supported in the
16 master bushing by horizontal shoulders at 35. Internally, the
17 slip bowl segments have at a location spaced beneath the tops of
18 the segments two complementary semi-circularly downwardly tapering
19 frustoconical cam surfaces 36 which in the lowered active position
22o of the slips (broken lines in Fig. 3 and full lines in Fig. 5)
1 engage correspondingly downwardly tapered external surfaces 37
22 formed on slips 19. Above the level of surfaces of 36, each of
23 the slip bowl segments 28 and 29 contains two circularly spaced
2a enlarged diameter recesses 38 having outer walls 39 tapering down-
25 wardly and frustoconically in correspondence with surfaces 36 and
26 37 and engageable with upper enlarged diameter similarly tapered
27 cam surfaces 40 on the slips. As seen in Fig. 6, each of the slips
2 has a circular extent corresponding closely to that of the mating
29 recess 38, to be confined closely therein in a manner transmitting
~0 rotary motion about axis 15 from the slip bowl to the slips.
31 In the upper inactive position of the slips (full lines in Fig. 3),
32 the larger diameter surfaces 40 of the slips move upwardly beyond
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1 the top of the slip bowl segments, and the lower reduced diameter
2 portions of the slips move into recesses 38, so that the slips can
3 move radially outwardly to positions spaced relatively far from the
outer surface of pipe 16. Internally, the slips 19 have inner
5 surfaces 41, which extend essentially cylindrically at the same
6 diameter as the outer surface of pipe 16, to grip and support that
7 pipe, and which desirably have teeth as shown for assuring effe~tive
8 gripping engagement with the pipe.
9 The slip carrier structure 18 may take the form essenti-
10 ally of a horizontally extending plate-like structure, containing
11 a central circular opening 42 (Fig. 2) through which the well pipe
12 extends vertically. Carrier 18 is preferably formed of two comple-
13 mentary essentially semi-circular sections or halves 43 and 44,
14 meeting or essentially meeting at surfaces 45 lying in the prev-
iously mentioned plane of separation 30 of the two slip bowl seg-
16 ments 28 and 29. These two sections 43 and 44 of the top carrier
17 18 may be detachably but rigidly secured together by two horizontal
18 parallel connector pins 45 and 46 received and closely confined
19 within aligned passages 47 in lugs 48 at the ends of the carrier
sections 43 and 44. Handle loops 49 connected to first ends of
21 the pins 45 and 46 facilitate insertion and removal of the pins
22 and prevent axial movement in one direction, while cotter keys
23 50 or the like extending through opposite ends of the pins can
2a releasably retain them against removal in the opposite direction.
The top plate or carrier structure 18 rigidly carries an
26 actuating ring 51, which extends circularly about axis 15 at a
27 location spaced radially outwardly from plate 18. This ring 51
28 may be formed from rigid metal rod of an appropriate diameter,
29 and may be constructed sectionally so that different portions of
~ the ring may separate from one another in the same plane 30 as
31 do the other previously mentioned parts. More particularly, a
32 first semi-circular section 52 of ring 51 may be attached rigidly
~716~ 590-59
1 to section 44 of the top carrier plate, while two additional
2 sections 53 and 54 may be carried by the second plate 43, with
3 an interruption in the ring being formed at 55 between the two
4 sections 53 and 54. All of these sections 52, 53 and 54 may be
connected to the top plate sections 43 and 44 in any appropriate
6 manner, desirably by provision at the location of each of the
7 slips 19 of two parallel mounting or connector parts 56 and 57 ^
8 having radially outer ends welded at 58 to the corresponding ring
9 segment, and having inner endswelded at 59 to the underside of the
corresponding plate 43 or 44. Directly beneath plate 43 or 44,
11 each of these pairs of mounting elements 56 and 57 may contain
12 horizontally aligned apertures 60 through which a horizontal pin
13 61 extends for pivotally attaching a corresponding slip suspending
14 link unit 62 from the top plate. One such link is provided at the
location of each of the slips, and is connected at its upper
16 end to the carrier structure 18 for relative pivotal movement about
17 a horizontal axis 63, and at its lower end to a corresponding one
18 of the slips 19 for relative pi.votal movement about a second
19 horizontal axis 64 extending parallel to axis 63. As will be
20 understood, these axes 63 and 64 are so disposed as to be tangent
21 to circles centered about well axis 15, and are oriented to allow
22 the slips to swing inwardly and outwardly relative to axis 15
2 as they move between the upper retracted positions of the slips
24 and the lower active position of the slips. To form the two pivota: .
connections, each link unit 62 is received about the corresponding pin
26 61 at a location between two of the connector members 56 and 57,
27 and may include a tube 65 fitting closely about that pin and
28 welded at its opposite ends to two parallel downwardly projecting
29 arms 66 pivotally connected at their lower ends to the associated
slip 19 by a pin 67. Each of the pins 61 may have a handle
31 loop 70 at one end and an aperture through which a cotter
32 key 71 or the like may extend at the opposite end of the pin, to
1~87~62
l retain the pin in its active position but 2ermit detachment of the
2 slips when desired.
3 Each of the top plate sections 43 and 44 is connected
4 movably to the corresponding slip bowl segment 28 or 29 by two of
5 the previously mentioned vertically extending guide or connector
6 units 20. As seen in Fig. 4, each of these connector units 20
7 includes an externally cylindrical vertical tube 72 which is
8 rigidly attached to the corresponding top plate section 43 or 44,
9 as by welding a horizontal disc 73 to the upper end of the tube and
lO then clamping that disc to the underside of plate 43 or 44 between
ll a shoulder 74 on a vertical rod 75 and the undersurface 76 of the
12 plate. A reduced diameter shank 77 of rod 75 extends upwardly
13 through apertures in disc 73 and plate 43 or 44, for connection
l~ at its upper threaded end to a nut 78 acting to clamp the parts
15 together. Tube 72 and rod 75 are in each case concentric about
16 an individual axis 79 of that particular guide unit, and both
17 project downwardly within a vertical cylindrical bore 80 in the
18 corresponding slip bowl segment 28 or 29. A cylindrical shouldered
l9 bushing 81 retained within the upper portion of bore ao slidably anc L
20 telescopically interfits with tube 72, to effectively guide the
21 tube and top plate 43 or 44 for only directly vertical movement
22 relative to the upper slip bowl structure. The tube 72 and connect~ !d
23 top plate are yieldingly urged upwardly by a vertical coil spring
24 21 which is received radially between tube 72 and rod 75, and which
25 extends downwardly beyond the lower end of tube 72 and through a
26 reduced diameter extension 83 of bore 80. At its lower end, spring
27 21 may bear downwardly at 84 against a bottom plate 85 secured to
28 the underside of the slip bowl segment by upward engagement of a
29 head 86 on rod 75 with plate 85. The upper enlarged diameter portic In
80 of the bore is of course long enough to receive tube 72 in the
31 lower active position of the slips. The four coil springs 21
2 toget ba~e eno~g~ ~trength - 1e~y AU~St-nt a~ly overcome the
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10~3716;~
1 weight of the carrier structure 18 and all of the connected slips
2 and other parts, and thus normally maintain the carrier structure
3 and slips in their upper full line retracted positions of Fig. 3.
4 This spring force may be overcome by pressing downwardly against
5 the ring structure 51. Preferably, the downward force thus
6 required to overcome the springs is relatively great to assure
7 against accidental downward actuation of the slips, and for this
8 purpose the re~uired force to overcome the springs, over and above
9 the force of gravity resulting from the weight of the carrier and
10 connected parts, is desirably at least about 100 pounds, and for
11 best results approximately 400 pounds. This downward force may the~
12 be exerted by one or more workmen standing on the ring structure 51
13 so that the weight of the workmen will move the carrier and slips
1~ downwardly.
~he latch element 22 for retaining the slips in their
16 lowered active positions may have the configuration illustrated in
17 Fig. 4, and be pivoted to the slip bowl segment 28 for relative
18 pivotal movement about a horizontal axis 88, as by extension of
19 pivot pin 89 through element 22 and a pair of mounting lugs 90
rojecting outwardly from section 28. An actuating arm 9~ of
21 lement 22 projects radially outwardly and may carry an arcuately
22 urved rod 92 received at the location of the previously mentioned
23 nterruption 55 in ring structure 51, and forming in effect a
24 ontinuation of that ring structure in the lower active position of
he slips. A spring 93 received within a cavity in element 22
26 (Fig. 5) yieldingly urges a pin 193 against the outer surface of
27 he slip bowl section 28, to yieldingly resist pivotal movement of
28 lement 22 in a counter-clockwise direction as viewed in Figs. 4
29 nd 5. An upwardly projecting portion 94 of element 22 has an
30 inwardly projecting hook portion with a downwardly facing shoulder
31 95, desirably inclined slightly as shown, which in the Fig. 5
32 atched condition of the parts engages an upwardly facing, preferabl~
\
10~716Z 590-59
1 directly horizontal latching shoulder 96 on top plate 43 to
2 positi~ely but releasably lock the carrier structure and slips in
3 the lowered active position of Fig. 5. The latch may be released
4 by downward deflection of actuating ring segment 92, which may be
5 foot operated downwardly by a workman.
6 To describe a cycle of operation of the device, assume
7 that a drill pipe 16 is already located in a position of vertical
8 extension through the rotary table and master bushing 12, and that
9 it is desired to utilize the device 10 for supporting the string
10 while a length of pipe is removed from the string. The two halves
11 of the device 10 may initially be separated from one another, as
12 represented in Fig. 1 in which one of the separated halves is
13 represented in broken lines at 196. Each of these halves includes
1~ a lower slip bowl segment 28 or 29 and an upper spring urged carrie~ .
15 plate half 43 or 44 with a connected ring element 52 or elements
16 53 and 54, and with the movably suspended slips, and further with
17 the latch element 22 being carried by one of the halves. The two
18 halves are moved separately to,positions about the pipe, and are
19 then secured together by insertion of the two connector pins 45 and¦
20 46 into the two top plates. The top plates then form together a
21 single rigid carrier structure by which all of the other elements
22 are carried in the relationship illustrated in full lines in Fig. 1
23 In this condition, the slip bowl structure 17 is lowered into the
24 opening 11 in the master bushing, to a position of support thereby.
25 The coil springs 82 normally retain the slip carrier and attached
26 slips in their upper retracted positions, in which the pipe 16
27 can be moved freely upwardly and downwardly without interference
28 by the slips, and with the opening through the device 10 being larg~
29 enough to pass enlarged joints of the drill pipe. When it is
desired to support the drill string in the rotary table by means
31 of the unit 10, the workmen press downwardly on the ring structure I
32 51, desirably by stepping on that ring at different locations about¦
11.
~ 0 87 1 6 Z 590_59
1 the pipe, as represented at 97 in Fig. 3. The combined weight of
2 the workmen thus presses the carrier and slips downwardly to the
3 Fig. '; position, causing an edge 98 of top plate 18 to engage cam
4 surface 99 of latch element 22 in a manner first deflecting the
5 upper portion of the latch element outwardly and then permitting
6 it to return inwardly to its Fig. 5 latching
7 condition. In this condition, the inner gripping surfaces of the
8 four slips are in simultaneous gripping contact with the outer
9 surface of the well pipe, so that when the pipe is then rel~ased
10 for downward movement the slips will be wedged more tightly
11 downwardly and inwardly against the pipe to effectively support its
12 entire weight. It is also noted that in this condition of the
13 apparatus the entire unit 10 can turn with the rotary table 14
14 and master bushing 13, so that rotation of the table and contained
15 unit 10 can be employed for turning the suspended pipe to make or
16 break a joint. When it is desired to again move the pipe 16
17 vertically, an operator presses downwardly with his hand or foot
18 on the actuating portion 92 of the latch element, to release the
19 latch and permit upward movement of the carrier and slips by the
20 force of coil springs 82.
21
22 While a certain specific embodiment of the present
23 invention has been disclosed as typical, the invention is of
24 course not limited to this particular form, but rather is
25 applicable broadly to all such variations as fall within the
26 ~ scope o he appended c1aims.
239
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