Power Positioner for Power Tong Units Background - Field of Art
This invention relates to apparatus used in connection with the drilling and servicing of
earthen boreholes, commonly called "wells," and more particularly to apparatus used to position
power tongs at desired locations to make up and break out threaded connections on tubular
goods.
Background - Related Art
Power tongs have come into widespread use in the oil and gas industry, especially on
drilling rigs in recent times, to make up and break out threaded connections on tubular goods,
referred to herein as tubulars. Tubulars include all manner of threaded connection goods such as
tubing, casing, and drill pipe. In particular, the use of power tongs to make up and break out drill
pipe threaded connections, commonly called tool joints, has greatly increased. Such connections
require high torque values, and consequently the tong units required to generate such torque
values are quite heavy.
The great weight of these power tongs, and increased emphasis on safety and efficiency
in rig operations has resulted in a move away from one of the earliest forms of tong "positioners"
- that being the tong hung on a line, which is routed over a pulley mounted high in the rig
derrick, to a counterweight that suspends the tong above the rig floor, yet permits it to be swung
into position and raised and lowered. This form of "positioner" does not restrain the tong from
swinging around and striking personnel and other equipment, and otherwise has limitations on its use.
In response, various types of powered positioners, particularly for positioning power
tongs, have been invented to positively position such tongs at desired positions with respect to
the rig floor, and more particularly to position the tong around the threaded connection to be
made up and broken out. A typical situation is the makeup or breakout of a drill pipe connection,
where the tool joint is in the rotary table (essentially in the center of the rig floor) several feet
above the rig floor. However, the power positioner must also be capable of placing the tong in
positions away from the center of the rig floor, for example to handle drill pipe connections in
the so-called rat hole or mousehole, which are displaced from the center of the rig floor. The
power positioner must preferably be in a relatively out of the way position on the rig floor, and
must position the power tong out of the way when not needed.
There exist other technologies to position tongs, including boom-type positioners and
those which run on stationary tracks typically disposed on the rig floor. The invention of the
present application affords another solution to the problem.
Summary of a Presently Preferred Embodiment of the Invention
The present invention, in one presently preferred embodiment, is a power positioner for
placement of tongs in a desired location about a rig floor. The term "tongs" as used herein
comprises any type of powered device with which to makeup and/or breakout threaded tubular
connections, whether it be a "make and break" device, conventional power tong, power tong unit
comprising a backup, etc. The invention comprises a vertically movable pedestal having a base
and a sliding carriage mounted on it. The sliding carriage preferably rides on a plurality of
rollers disposed between the base and the carriage, and is movable back and forth horizontally by
a pair of hydraulic cylinders. The base is rotationally mounted on the pedestal, such that rotation
of the base in turn rotates the carriage in a substantially horizontal plane. A powered pinion and ring gear assembly provides the rotary movement between the base and the pedestal. A lift
assembly is mounted on the carriage, and in the preferred embodiment comprises two arms
pivotally mounted on the sliding carriage, with a rotating gambrel joining the two arms. A
power tong may be suspended from the gambrel. Hydraulic cylinders attached between the lift
assembly and the sliding carriage permit pivoting the lift assembly about its pivot points, so that
a power tong hanging therefrom is both raised/lowered and moved backward/forward by the
pivoting motion. Controls are operationally connected to the power positioner, via any
combination of mounting on the tong, at a remote location connected by a control umbilical, or
via radio frequency connection, to raise and lower the pedestal; rotate the base on the pedestal;
pivot the lift assembly; and move the sliding carriage backward and forward, thereby permitting
a power tong to be positioned at a desired location with respect to the rig floor.
Brief Description of the Drawings
Fig. 1 is a perspective view of a typical rig floor setting showing the apparatus in a fully
retracted position, with the power tong in a stored position.
Fig. 2 is an exploded view of the apparatus, in a perspective view of the apparatus in an
extended position, with the power tong positioned to engage a drill pipe connection.
Figs. 3 -5 are side views of the apparatus, in several different positions.
Fig. 6 is another side view of the invention.
Description of the Presently Preferred Embodiment
While those skilled in the relevant art will recognize that various changes can be made
from the disclosed embodiment of the invention, without departing from the spirit of the
invention, with reference to the drawings one presently preferred embodiment will be described.
It is understood that the term "power tong," as used in this application, encompasses any
form of powered device used to make up and/or break out threaded tubular connections (on any
type of tubular, including drill pipe, tubing, casing, etc.), and includes drill pipe tongs, casing
tongs, "make/break" devices, etc. It is further understood that the invention may have
application in many different settings; as a matter of convenience only, the invention is described
in connection with its deployment on a drilling or workover rig. However, it is equally
applicable to positioning tongs in a shop environment, for example.
Figs. 1 best serves to illustrate a typical installation of the power positioner on a rig floor,
in proximity to a threaded tubular connection to be made up or broken out, such as a drill pipe
connection. While the power positioner may be installed at various desired locations about the
rig floor, one possible location is to one side of the rotary table, to permit ready access to tubulars
both in the rotary and in the mousehole. Fig. 1 shows the apparatus in a retracted position, with
the tong in a stored position substantially over the pedestal. With the power positioner mounted
in front of the drawworks, in the retracted position the entire apparatus (including the power tong
mounted thereon) is out of the way of most rig operations, yet is positioned to readily be placed
into service when needed.
Fig. 2 is an exploded view of the apparatus. With reference to Figs. 1 and 2, power
positioner 10 comprises a vertically movable pedestal 20 mounted on or in a desired location, for
example mounted on a rig floor and extended down below the rig floor. Alternatively, pedestal
20 may be mounted on the floor of a shop or other similar setting. Preferably, pedestal 20 is
vertically movable by hydraulic means, although mechanical means such as a roller and flat gear
combination could be used. As can additionally be seen in Fig. 2, a base 30 is rotationally
mounted on pedestal 20, preferably atop pedestal 20. A powered pinion and ring gear assembly
40 permits controlled rotation of base 30 on pedestal 20. A carriage 40 is slidably disposed on
base 30, and in the presently preferred embodiment, carriage 40 rides on a plurality of rollers 60
which are disposed between base 30 and carriage 50, preferably mounted on base 30.
A means for moving carriage 50 on base 30 is provided. In the preferred embodiment,
this means for moving comprises at least one, and preferably a pair of hydraulic cylinders 70
mounted between base 30 and carriage 50. Actuation of hydraulic cylinders 70 moves carriage
50 between a retracted position and an extended position, as is later described.
Both horizontal and vertical movement of a power tong is provided by a lift assembly
preferably mounted on carriage 50, from which a power tong is suspended. In a presently
preferred embodiment, the lift assembly comprises at least one, and preferably a pair, of arms 80
rotatably mounted on carriage 50. A means for rotating arms 80 about their pivot point is
provided. The presently preferred embodiment comprises an extensible means such as hydraulic
cylinder 90 connected between arms 80 and carriage 50, which rotates arms 80 with extension
and retraction of the hydraulic cylinder. Preferably, a gambrel 100 joins arms 80, and power
tong 110 is suspended from gambrel 100. Gambrel 100 typically suspends power tong 110 such
that power tong 110 can swing back and forth to a limited degree, with rotation of gambrel 100
about its longitudinal axis. An elastic means 130, such as a spring or pneumatic cylinder, can be
disposed between power tong 110 and gambrel 100, to provide some "cushioning" to the weight
of power tong 110 hanging from gambrel 100, and additionally to permit power tong 110 to
move up or down while engaged on the tubular, to permit the tong to compensate for thread
makeup and breakout (either extending or contracting). Alternatively, power tong 110 could be
mounted to arms 80 via different configurations of rigid members, or even by flexible members such as cables and the like, from arms 80.
While some degree of movement may be desirable for final positioning of power tong
110 on a connection, preferably a stabilizer 120 is provided, that connects between power tong
110 or the means by which it is suspended from arms 80, and some other part of the apparatus,
for example to arms 80. As can be seen in the figures, one embodiment has stabilizer 120
mounted between arm 80 and gambrel 100. Stabilizers 120 may be hydraulic, pneumatic, or
spring cylinders, etc. to dampen and restrain the degree to which power tong 110 can swing.
The preferred embodiment of the invention can also comprise controls of forms well
known in the relevant art to control rotation of the base on the pedestal; movement of the
pedestal up and down; movement of the carriage back and forth on the base; and movement of
the arms. Further, controls may be provided to operate the various aspects of the power tong unit
itself. Such controls may be connected to the various parts of the power positioner and power
tong unit via a hydraulic line/electric cable umbilical, routed to a conveniently placed control
panel; or communication via radio waves between controls and the controlled mechanisms can
be used. Yet another embodiment has controls for both the power positioner and the power tong
unit mounted on the power tong unit, for easy manipulation by the power tong operator.
Operation of the power positioner
Figs. 3 - 6 illustrate the power positioner in different positions, in a typical sequence of
use in positioning a power tong unit onto a tubular threaded connection. While the particular
embodiment illustrated is on a rig floor setting, as earlier mentioned it is understood that the
scope of the invention lends itself to use in other settings, such as a shop for manipulation of bottom hole assemblies, etc.
In Fig. 3, the apparatus, and hence power tong 110, is in a substantially fully retracted
position, that is, as far back from the tubular as can be positioned. As can be seen, carriage 50 is
retracted on base 30 (to the right in Fig. 3 as illustrated) by hydraulic cylinders 70, and arms 80
are pulled back via hydraulic cylinders 90 to their fully retracted position. Power tong unit 110
is therefore out of the way of other rig operations. Fig. 3 illustrates a key space saving aspect of
the invention, wherein the pedestal is (in a retracted position) largely below the rig floor (or shop
floor or the like).
Fig. 4 is a next exemplary position in the course of moving power tong 110 from a
retracted position to a position around the tubular. Cylinders 70 are extended to rotate arms 80 to
a forward position. In this figure, carriage 50 is still in a retracted position on base 30.
Fig. 5 next shows power tong 110 in a position around the tubular. Carriage 50 has been
advanced on base 30, and the combination of lateral movement of carriage 50 and arms 80 is
sufficient to place power tong 110 in a desired position around the tubular. It is understood that
the combination and sequence of lateral movement of power tong 110, by both movement of
carriage 50 and rotation of arms 80, can be in any desired sequence, and to any desired degree.
The dimensions of the various components can be adjusted to suit differing settings.
Fig. 6 additionally shows the component of vertical movement of power tong 110
achieved by vertical movement of pedestal 20. Rotation of base 30 on pedestal 20 can give yet another degree of movement of power tong 110.
It can be readily appreciated that a power tong can thus be positioned by the present
invention in a vertical plane, by a combination of pedestal movement and rotation of the arms;
and in a horizontal plane, by a combination of movement of the carriage on the base, rotation of the arms, and rotation of the base on the pedestal.
It can be readily seen by the figures and description, that the various components of the
invention permit movement of the power tong in both horizontal and vertical directions, and that
different positions can be readily achieved via a combination of such movements.
While the description set forth above contains many details of the preferred embodiment,
same are made in order to disclose one of the presently preferred embodiments and not by way of
limitation. Various changes could be made while staying within the scope of the present
invention, for example dimensions of the various elements; scope or extent of movement of the
various mechanisms of the power positioner; the power positioner can be used to manipulate
power tongs used to make up and/or breakout any type of threaded tubular, including drill pipe,
tubing, or casing; the invention can be deployed in the field on any type of rig or other similar
setting, or can be used in a shop.
Therefore, the scope of the invention is to be measured not by the disclosed
embodiments, but by the scope of the appended claims and their legal equivalents.