Information
-
Patent Grant
-
6533519
-
Patent Number
6,533,519
-
Date Filed
Thursday, July 20, 200024 years ago
-
Date Issued
Tuesday, March 18, 200322 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Walsh; Donald P.
- Shapiro; Jeffery A.
Agents
-
CPC
-
US Classifications
Field of Search
US
- 414 2254
- 414 2257
- 414 2258
- 414 2259
- 414 2261
- 414 2262
- 175 85
-
International Classifications
-
Abstract
A pipe handling apparatus for transporting a joint of pipe between a position adjacent a pipe storage rack and a rig floor elevated above the pipe storage rack is provided. The pipe handling apparatus includes a support frame, substantially horizontally disposed platform supported by the support frame having a pipe receiving groove formed therein for receiving the joint of pipe, a carriage member, and a pusher member. The carriage member is movable from a lowered position wherein the joint of pipe which is positioned in the pipe receiving groove of the platform is supported in a substantially horizontal position and a raised position wherein the carriage member supports a first end of the joint of pipe at an elevated position relative to an opposed second end of the joint of pipe. The pusher member is movable along the pipe receiving groove between a retracted position and an extended position. In the retracted position, the pusher member is positioned near the second end of the pipe receiving groove to laterally support the joint of pipe when the first end of the joint of pipe is elevated relative to the second end. In the extended position, the pusher member is moved a selected distance away from the second end of the pipe receiving groove toward the first end of the pipe receiving groove so as to cause the second end of the joint of pipe to move through the pipe receiving groove towards the first end of the pipe receiving groove along a substantially horizontal plane and thereby cause the first end of the joint of pipe to be moved to a position overlying the rig floor.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
Not applicable.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to materials lifting apparatuses, and more particularly, but not by way of limitation, to an improved pipe handling apparatus for transporting pipe between a pipe storage rack and a rig floor which is elevated above the pipe storage rack.
2. Brief Description of the Related Art
In the drilling of a well, tubular members such as drill pipe, casing, and production tubing must be transported between a pipe storage rack and a drilling rig floor. For instance, it is necessary periodically to pull the drill string out of the well bore (“tripping out”) to replace the drill bit and in turn run the drill string back into the well bore. This process involves a series of repetitive steps in which joints of pipe are withdrawn from the well bore, disconnected, and stored on the pipe storage rack. The process is then repeated in reverse order to replace the drill string in the well bore. Due to the fact that the drilling rig floor can be as much as 20 to 30 feet above ground level, numerous devices have been previously proposed to assist in the movement of the tubular members between the pipe storage rack and the rig floor. Such devices are generally complex in construction, designed for use with a particular drilling rig, and not easily transported from one drilling rig to another.
As with the drilling process, the servicing of a well involves a series of repetitive steps to replace production tubing or maintenance downhole equipment. Rigs used for servicing wells are often referred to as “workover” rigs. Workover rigs generally have a rig floor positionable over the surface equipment of the well and a mast which supports the elevators. The elevators are used to raise and lower the production tubing into and out of the well bore and to handle the individual joints of pipe once they are on the rig floor.
The rig floor of a workover rig can be elevated as much as 6 to 15 feet above ground level depending on the amount of surface equipment utilized with the well. However, unlike with drilling rigs, it has been the practice to manually transport the pipe between the rig floor and the pipe rack. This involves a worker rolling a joint of pipe off the pipe rack onto a platform known as a “catwalk”. The worker then drags of the pipe toward the rig and raises one end of the pipe toward the rig floor to the point where the elevators of the rig can latch onto the end of the pipe. The process is reversed when removing pipe from the rig. This practice is extremely labor intensive, time consuming, and dangerous.
To this end, a need exists for an improved pipe handling apparatus which is simple in construction, easy to transport and operate, and which is adapted to be used with a variety of different rigs. It is to such an apparatus that the present invention is directed.
BRIEF SUMMARY OF THE INVENTION
The present invention is directed to a pipe handling apparatus for transporting a joint of pipe between a position adjacent a pipe storage rack and a rig floor elevated above the pipe storage rack. The pipe handling apparatus includes a support frame, a horizontally disposed platform, a carriage member, and a pusher member. The platform has a pipe receiving groove formed therein for receiving the joint of pipe. The pipe receiving groove has a first end and an opposing second end.
The carriage member is positioned near the first end of the pipe receiving groove and is connected to the support frame. The carriage member is movable from a lowered position wherein the joint of pipe which is positioned in the pipe receiving groove of the platform is supported in a substantially horizontal position and a raised position wherein the carriage member supports a first end of the joint of pipe at an elevated position relative to an opposed second end of the joint of pipe. The elevated position of the first end of the joint of pipe is at a height at least the height of the rig floor while the second end of the joint of pipe remains positioned in the pipe receiving groove.
The pusher member is in alignment with the pipe receiving groove so as to be engageable with the second end of the joint of pipe when the joint of pipe is positioned in the pipe receiving groove. The pusher member is movable along the pipe receiving groove between a retracted position and an extended position. In the retracted position, the pusher member is positioned near the second end of the pipe receiving groove to laterally support the joint of pipe when the first end of the joint of pipe is elevated relative to the second end. In the extended position, the pusher member is moved a selected distance away from the second end of the pipe receiving groove toward the first end of the pipe receiving groove so as to cause the second end of the joint of pipe to move through the pipe receiving groove towards the first end of the pipe receiving groove along a substantially horizontal plane and thereby cause the first end of the joint of pipe to be moved to a position overlying the rig floor.
The features and advantages of the present invention will become apparent from the following detailed description when read in conjunction with the accompanying drawings and appended claims.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
FIG. 1
is a side elevational view of a pipe handling apparatus constructed in accordance with the present invention having a carriage member shown in a lowered position.
FIG. 2
is a side elevational view of the pipe handling apparatus of the present invention shown with the carriage member in a raised position.
FIG. 3
is an end elevational view of the pipe handling apparatus of the present invention shown positioned adjacent a pipe storage rack and aligned with the center of a floor of a workover rig.
FIG. 4
is an enlarged side elevational view of a portion of the pipe handling apparatus of the present invention shown with the carriage member in the raised position.
FIG. 5
is a side elevational view of a portion of the pipe handling apparatus of the present invention illustrating the raised end of the pipe moved to a position overlying the rig floor.
FIG. 6
is a perspective view of a first end of the platform and the carriage member shown in the lowered position.
FIG. 7
is a perspective view of a lower portion of the platform showing the carriage assembly in the lowered position.
FIG. 8
is a perspective view of a portion of the platform and a pusher assembly.
FIG. 9
is a cross sectional view taken along line
9
—
9
of FIG.
8
.
FIG. 10
is a cross sectional view taken along line
10
—
10
of
FIG. 8
showing an end view of the pusher assembly.
FIG. 11
is a side elevational view of the pusher assembly.
FIG. 12
is a perspective view of a jack assembly of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to the drawings and more particularly to
FIGS. 1-5
, a pipe handling apparatus
10
constructed in accordance with the present invention is shown. The pipe handling apparatus
10
adapted to be positioned adjacent a pipe storage rack
12
(
FIG. 3
) for facilitating the transport of a joint of pipe
14
between the pipe storage rack
12
and a rig floor
16
(
FIGS. 3 and 5
) which is typically elevated a distance above the pipe storage rack
12
. The pipe handling apparatus
10
includes a support frame
18
, a platform
20
, a carriage assembly
22
, a pusher assembly
24
, a pair of jack assemblies
26
, and a hydraulic assembly
28
.
The support frame
18
is an elongated rectangular structure having a first end
30
, a second end
32
, a first side
34
, a second side
36
, an upper side
38
, and a lower side
40
. The support frame
18
is constructed of a plurality of rigid tubular members interconnected to one in a suitable manner, such as by welding. The support frame
18
is provided with a stairway
42
to facilitate a worker's movement between the upper side
38
and the lower side
40
of the support frame
18
.
The platform
20
is secured to the upper side
38
of the support frame
18
so that the platform
20
is substantially horizontally disposed when the pipe handling apparatus
10
is in use. As best shown in
FIGS. 8-10
, the platform
20
is provided with a longitudinally extending pipe receiving groove
44
. As shown in
FIGS. 8 and 9
, the pipe receiving groove
44
is configured to hold the joint of pipe
14
to be transported to the rig floor
16
.
The pipe receiving groove
44
has a first end
46
(
FIG. 6
) and an opposing second end
48
(
FIG. 8
) and is formed by angling opposing portions
50
of the platform
20
in a downward direction (FIG.
9
). The platform
20
further includes an elongated slot
51
extending through the platform
20
and running the length of the pipe receiving groove
44
. The slot
44
is defined by the downwardly angled portions
50
of the platform
20
. As shown in
FIG. 6
, the platform
20
is provided with an elongated opening
52
in communication with the first end
46
of the pipe receiving groove
44
for receiving a portion of the carriage assembly
22
in a manner to be discussed below.
Returning to
FIGS. 1
,
2
and
8
, the platform further includes a hand rail
5
.
4
which is adapted to be positioned on either side of the platform
20
, and the platform includes a plurality of holes
56
on either side of the pipe receiving groove
44
for positioning a pair of stop members
58
(only one shown in
FIG. 8
) adjacent the pipe receiving groove
44
of the platform
20
for preventing the joint of pipe
14
from rolling through the pipe receiving groove
44
and across the platform
20
.
Referring now to
FIGS. 4-7
, the carriage assembly
22
includes a carriage member
60
and a cylinder
62
. The carriage member
60
is secured to the support frame
18
such that the carriage member
60
is positioned near the first end
46
of the pipe receiving groove
44
within the opening
52
of the platform
20
. The cylinder
62
functions to move the carriage member
60
from a lowered position (
FIGS. 1
,
6
, and
7
) wherein the joint of pipe
14
which is positioned in the pipe receiving groove
44
of the platform
20
is supported in a substantially horizontal position and a raised position (
FIGS. 2
,
4
, and
5
) wherein the carriage member
60
supports a first end
64
of the joint of pipe
14
at an elevated position relative to an opposing second end
66
of the joint of pipe
14
while the second end
66
of the joint of pipe
14
remains positioned in the pipe receiving groove
44
.
The carriage member
60
includes a V-shaped trough portion
68
which is positioned within the opening
52
of the platform
20
and configured to substantially correspond with the shape and size of the pipe receiving groove
44
such that the upper surface of the trough portion
68
functions as an extension of the pipe receiving groove
44
when the carriage member
60
is in the lowered position. The carriage member
60
further includes a bracket portion
70
extending from the lower side of the trough portion
680
.
As shown in
FIG. 5
, the trough portion
68
has a first end
72
and an opposing second end
74
. The bracket portion
70
has a proximal end
76
connected to the first end
72
of the trough portion
68
, a medial portion
78
pivotally connected to a pair of brackets
80
of the support frame
18
at a pivot point
82
located below the platform
20
, and a distal end
84
. The trough portion
68
is further supported in the lowered position by a pair of V-shaped support members
85
(
FIG. 7
) extending from the lower side of the platform.
20
in alignment with the opening
52
of the platform
20
. The second end
74
of the trough portion
68
of the carriage member
60
is provided with a pair or rollers
87
for rollingly supporting the first end
64
of the joint of pipe
14
in a manner to be discussed below.
The cylinder
62
has a first end
86
, a second end
88
, and a reciprocating rod
90
extending from the second end
88
of the cylinder
62
. The first end
86
of the cylinder
62
is pivotally secured to the support frame
18
below the platform
20
, and the distal end of the reciprocating rod
90
is pivotally connected to the distal end
84
of the bracket portion
70
of carriage member
60
, as shown in
FIGS. 4 and 5
.
Referring now to
FIGS. 1
,
2
,
8
,
10
, and
11
, the pusher assembly
24
includes a pusher member
92
and a cylinder
94
. The pusher member
92
is positioned in alignment with the pipe receiving groove
44
so as to be engageable with the second end
66
of the joint of pipe
14
when the joint of pipe
14
is positioned in the pipe receiving groove
44
. The cylinder
94
functions to move the pusher member
92
along the pipe receiving groove
44
between a retracted position and an extended position. In the retracted position, the pusher member
92
is positioned near the second end
48
of the pipe receiving groove
44
to laterally support the joint of pipe
14
when the first end
64
of the joint of pipe
14
is elevated relative to the second end
66
. In the extended position, the pusher member
92
is moved a selected distance away from the second end
48
of the pipe receiving groove
44
toward the first end
46
of the pipe receiving groove
44
so as to cause the second end
66
of the joint of pipe
14
to move through the pipe receiving groove
44
towards the first end
46
of the pipe receiving groove
44
along a substantially horizontal plane and thereby cause the first end
64
of the joint of pipe
14
to be moved to a position overlying the rig floor
16
(FIG.
5
).
The pusher member
92
includes a semi-circular shaped pipe engaging portion
96
positioned above the platform
20
and a bracket
98
extending from the pipe engaging portion
96
down through the slot
51
of the platform
20
. The pusher member
92
further includes a pair of rollers
100
for rollingly supporting the pusher member
92
on the platform
20
.
The cylinder
94
has a first end
102
, a second end
104
, and a reciprocating rod
106
extending from the second end
104
of the cylinder
94
. The cylinder
94
is secured to the support frame
18
below the platform
20
in a parallel relation to the pipe receiving groove
44
and the distal end of the reciprocating rod
106
is rigidly connected to a lower end of the bracket
98
of the pusher member
92
.
Referring now to
FIGS. 1
,
2
and
12
, each of the jack assemblies
26
is connected to the support frame
18
for selectively adjusting the height of the platform
20
relative to the height of the pipe storage rack
12
(FIG.
3
). Each of the jack assemblies
26
includes a hydraulic cylinder
108
with a foot
110
provided on the end of a reciprocating rod
112
of the cylinder
108
. The foot
110
is pivotally attached to the reciprocating rod
112
and includes a base member
114
and a pair of guide plates
116
extending upwardly therefrom. The foot
110
of the jack assemblies
26
swivels on the end of the reciprocating rod
112
and the guide plates
116
support the foot
110
between a pair of transverse support members
118
of the support frame
18
. The jack assemblies
26
permit the platform
20
to be raised and lowered as desired. The height of the platform
20
is adjusted so that the platform
20
is lower than the level of the pipe racks
12
when the joint of pipe
14
is being rolled onto the platform
20
and the platform
20
is positioned above the level of the pipe racks
12
when the joint of pipe
14
is being rolled from the platform
20
to the pipe racks
12
.
The cylinders
62
,
94
, and
108
can be any suitable cylinders known in the art, such as double-acting hydraulic cylinders. To this end, the hydraulic assembly
28
includes a hydraulic tank
119
, an engine
120
, and a control panel
122
which includes corresponding control valves for actuating each of the cylinders
62
,
94
. The cylinder
108
of jack assembly
26
is operated by a valve
124
mounted on the support frame
18
(FIG.
12
). A
20
horsepower engine with a 9 gallon per minute capacity has been found to be suitable. The control panel
122
is preferably portable whereby a workman can position the control panel
122
in a convenient and safe location at the work site. Because the use of operation of hydraulic circuits are well known in the art, as well as their various components, the hosing used in the present invention has been omitted from the drawings for the sake of clarity.
Operation
The pipe handling apparatus
10
can be transported to the work site by any suitable means, such as a low-bed trailer or truck (not shown). With the pipe handling apparatus
10
transported to the work site, the pipe handling apparatus
10
is unloaded and positioned adjacent the pipe storage rack
12
in a parallel relationship to the joints of pipe
14
on the pipe storage rack
12
and adjacent the rig floor
16
with the pipe receiving groove
44
of the platform
20
in a substantially perpendicular relationship thereto. The height of the pipe handling apparatus
10
may then be adjusted, if necessary, to position the platform
20
at a height level with or slightly below the height of the pipe storage rack
12
to permit the joints of pipe
14
on the pipe storage rack
12
to be easily transported onto the platform
26
and into the pipe receiving groove
44
merely by rolling the individual joints of pipe
14
. The height of the pipe handling apparatus
10
is adjusted by an operator actuating the cylinders
108
of the jack assemblies
26
so as to cause the reciprocating rods
112
and thus the foot
110
to be extended and thus raise the support frame
18
and the platform
20
. Suitably sized support or blocking members (not shown), such as timbers, may then be positioned under the lower side
40
of the support frame
18
. The reciprocating rods
112
of the jack assemblies
26
are then retracted so that the support frame
18
is supported on the support members. It will be appreciated that if the pipe handling apparatus
10
is being utilized to transport joints of pipe
14
from the rig floor
16
to the pipe storage rack
12
, it will be desirable to position the platform
20
at a height level with or slightly above the height of the pipe storage rack
12
to permit the joints of pipe
14
on the platform
20
to be easily transported onto the pipe storage rack
12
merely by rolling the individual joints of pipe
14
.
To transport a joint of pipe
14
from the pipe storage rack
12
to the rig floor
16
, the carriage member
60
is positioned in the lowered position and the pusher member
92
is positioned in the retracted position. An operator then rolls the joint of pipe
14
(as shown in
FIG. 3
) onto the platform
20
and into the pipe receiving groove
44
so that the first end
64
of the joint of pipe
14
is positioned in the trough portion
68
of the carriage member
60
(FIG.
6
). The operator then causes the cylinder
62
of the carriage assembly
22
to be actuated to extend the rod
90
and cause the carriage member
60
to be rotated about the pivot point
82
as represented by arrow
126
in
FIGS. 2 and 4
and thus the trough portion
68
of the carriage member
60
to move to the raised position (
FIGS. 2
,
4
, and
5
) whereby the first end
64
of the joint of pipe
14
is elevated to a height at least the height of the rig floor
16
while the second end
66
of the joint of pipe
14
remains positioned in the pipe receiving groove
44
.
The operator then causes the cylinder
94
of the pusher assembly
24
to be actuated to retract the rod
106
and cause the pusher member
92
to be moved along the pipe receiving groove
44
from the retracted position to the extended position, as represented by arrow
128
in
FIG. 2
, and thus cause the second end
66
of the joint of pipe
14
to move through the pipe receiving groove towards the first end
46
of the pipe receiving groove
44
along a substantially horizontal plane and thereby cause the first end
64
of the joint of pipe
14
to be moved to a position overlying the rig floor
16
(FIG.
5
). With the first end
64
of the joint of pipe
14
overlying the rig floor
16
, the carriage member
60
may be moved to the lowered position thereby lowering the first end
64
of the joint of pipe
14
onto the rig floor
16
where operators on the rig floor
16
can latch onto the first end
64
of the joint of pipe
14
with the elevators (not shown) of the rig and lift the joint of pipe
14
onto the rig floor
16
. The pusher member
92
is then returned to the retracted position to receive another joint of pipe
14
.
When the pipe handling apparatus
10
is employed to remove a joint of pipe
14
from the rig floor
16
, the first end
64
of the joint of pipe
14
is positioned on the carriage member
60
with the carriage member
60
in the raised position and the second end
66
of the joint of pipe
14
is positioned in engagement with the pusher member
92
with the pusher member
92
in the extended position. The pusher member
92
is then moved to the retracted position whereby the weight of the joint of pipe
14
causes the joint of pipe
14
to slide along the pipe receiving groove
44
and over the rollers
87
of the carriage member
60
toward the second end
48
of the pipe receiving groove
44
. The carriage member
60
is the moved to the lowered position and the joint of pipe
14
transferred to the pipe storage rack
12
.
From the above description it is clear that the present invention is well adapted to carry out the objects and to attain the advantages mentioned herein as well as those inherent in the invention. While presently preferred embodiments of the invention have been described for purposes of this disclosure, it will be understood that numerous changes may be made which will readily suggest themselves to those skilled in the art and which are accomplished within the spirit of the invention disclosed and as defined in the appended claims.
Claims
- 1. A pipe handling apparatus for transporting a joint of pipe between a position adjacent a pipe storage rack and a rig floor elevated above the pipe storage rack, the joint of pipe having a first end and an opposing second end, the apparatus comprising:a support frame having a first end, a second end, a first side, a second side, an upper end, and a lower end; a platform secured to the upper end of the support frame such that the platform is fixed in a substantially horizontal position and extends continuously between the first and second sides of the support frame and the first and second ends of the support frame, the platform having a pipe receiving groove formed therein for receiving the joint of pipe, the pipe receiving groove having a first end and an opposing second end, the platform forming a substantially flat, continuous surface extending along each side of the pipe receiving groove from the first end of the platform to the second end of the platform so as to permit an individual to walk along the length of the pipe receiving groove on either side of the pipe receiving groove while the joint of pipe is being transported between the pipe storage rack and the rig floor; a carriage member positioned near the first end of the pipe receiving groove and connected to the support frame, the carriage member movable from a lowered position wherein the joint of pipe which is positioned in the pipe receiving groove of the platform is supported in a substantially horizontal position and a raised position wherein the carriage member supports the first end of the joint of pipe at an elevated position relative to the second end of the joint of pipe, the elevated position of the first end of the joint of pipe being at a height at least the height of the rig floor while the second end of the joint of pipe remains positioned in the pipe receiving groove; and a pusher member in alignment with the pipe receiving groove so as to be engageable with the second end of the joint of pipe when the joint of pipe is positioned in the pipe receiving groove, the pusher member movable along the pipe receiving groove between a retracted position and an extended position, in the retracted position the pusher member is positioned near the second end of the pipe receiving groove to laterally support the joint of pipe when the carriage member is in the raised position supporting the first end of the joint of pipe in an elevated position relative to the second end and in the extended position the pusher member is moved a selected distance away from the second end of the pipe receiving groove toward the first end of the pipe receiving groove so as to cause the second end of the joint of pipe to move through the pipe receiving groove towards the first end of the pipe receiving groove along a substantially horizontal plane when the carriage member is in the raised position supporting the first end of the joint of pipe in an elevated position relative to the second end of the joint of pipe and thereby cause the first end of the joint of pipe to be moved to a position overlying the rig floor.
- 2. The pipe handling apparatus of claim 1 wherein the platform further has an elongated slot extending through the plate and in a parallel relationship with respect to the pipe receiving groove, wherein the pusher member includes a pipe engaging portion positioned above the platform and a bracket extending from the pipe engaging portion down through the slot, and wherein the pipe handling apparatus further comprises:a first cylinder having a first end, a second end, and a reciprocating rod extending from the second end of the cylinder, the first cylinder secured to the support frame below the platform in a parallel relation to the pipe receiving groove and the reciprocating rod connected to the bracket of the pusher member; and means for selectively actuating the rod of the first cylinder between a first position wherein the pusher member is positioned in the retracted position and a second position wherein the pusher member is positioned in the extended position.
- 3. The pipe handling apparatus of claim 2 wherein the pipe engaging portion is rollingly supported on the platform.
- 4. The pipe handling apparatus of claim 1 wherein the platform further has a carriage receiving opening in communication with the pipe receiving groove, wherein the carriage includes a trough portion positioned in the carriage receiving opening when the carriage is in the lowered position and a bracket portion, the trough portion having a first end and an opposing second end, the bracket portion having a proximal end connected to the first end of the trough portion, a medial portion pivotally connected to the support frame at a location below the platform, and a distal end, and wherein the pipe handling apparatus further comprises:a second cylinder having a first end, a second end, and a reciprocating rod extending from the second end of the cylinder, the second cylinder pivotally secured to the support frame below the platform and the reciprocating rod pivotally connected to the distal end of the bracket portion of carriage; and means for selectively actuating the rod of the second cylinder between a first position wherein the carriage is positioned in the lowered position and a second position wherein the carriage is rotated so as to cause the second end of the trough portion of the carriage to be moved to raised position.
- 5. The pipe handling apparatus of claim 4 wherein the trough portion is substantially V-shaped.
- 6. The pipe handling apparatus of claim 4 wherein the second end of the trough portion is provided with a pair of rollers for rollingly supporting the joint of pipe when the carriage is in the raised position and the pusher member is being moved from the retracted position to the extended position.
- 7. The pipe handling apparatus of claim 1 further comprising:a plurality of jack assemblies connected to the support frame for selectively adjusting the height of the platform relative to the height of the pipe storage rack.
- 8. The pipe handling apparatus of claim 1 wherein the platform further comprises a hand rail extending upwardly from at least one of the first and second sides of the platform.
- 9. The pipe handling apparatus of claim 1 wherein the platform further has a plurality of holes adjacent the pipe receiving groove on each side of the pipe receiving groove, and wherein the pipe handling apparatus further comprises:a plurality of stop members positioned in the holes of the platform on the side of the pipe receiving groove opposite the pipe storage rack and extending upwardly from the platform to prevent the joint of pipe from rolling through the pipe receiving groove.
US Referenced Citations (24)