This invention relates to apparatus used to manipulate pipe being installed into, or removed from, wells. It may be used with top drives or with general purpose hoist equipment on drilling rigs.
Pipe strings used in wells are usually threadedly connected assemblies. They are usually joined one stand at a time. A stand may consist of one or more pipe sections. The stands consisting of more than one section are usually pre-torqued at the pre-assembled connections.
Pipe installation rates favor the big rigs, largely because the big rigs have the vertical space needed to handle the larger number of pipe sections per stand. The vertical space is always limited and the length of the vertical pipe manipulating apparatus is limited. Excesses length of manipulation gear may reduce the number of pipe sections per stand.
In recent years, link arms that carry a single stand elevator to engage the on-coming pipe stand while the main hoist is lowering the pipe string into the well has added length to the manipulation gear. It is desirable to use telescoping link arms that can draw the new stand into the pipe gripping arrangement. That creates a problem.
A conventional telescoping link arm has a maximum length somewhat less than twice the minimum length. It is the minimum length that conflicts with the limited vertical space matter. There is a need for a link arm that can extend more than twice its minimum length. This invention addresses that matter.
A body that can be attached to a top drive or to rig swivel arrangements has two link arms attached that can carry a single stand elevator. The link arms can be tilted to bring the single stand elevator into engagement with a nearby stand. The link arms telescope to allow them to lift a new stand into a pipe gripping arrangement. The novel link arm telescopes in both axial directions from a central body. It can extend to more than twice its shortest length. The apparatus can support most known pipe gripping arrangements.
These and other objects, advantages, and features of this invention will be apparent to those skilled in the art from a consideration of this specification, including the attached claims and appended drawings.
The exemplary drawings illustrate apparatus capable of practicing the points of novelty claimed. They embody the preferred configuration in a general sense. They should not be construed in a limiting sense.
In the formal drawings, some details that do not bear upon points of novelty, and are well within the scope of those skilled in the art, are omitted in the interest of descriptive clarity. Such omissions may include weld lines, some threaded fasteners, pins, seal details, and the like.
In normal use the apparatus will be fitted with a pipe engagement device of the users choice. The apparatus, in turn, will be carried by a top drive or a traveling block or swivel. Such arrangements are well known by those skilled in the related art and none are shown in the present drawings.
Some hydraulic linear motors are preferred in the design and some source of fluid power is essential in their usual operation. Such sources are usually present on the drilling rig and their familiarity is likely preferred by operating personnel. The usual related power circuitry is not shown. Electrically powered linear motors are available to replace the preferred hydraulic cylinders. Such options are well known and none are presented in the present drawings.
Bails 8 support the apparatus by way of links 9 secured to the cross frame 2. The pipe engagement device PE is shown carried by main arbor 1. The device PE is not part of the present invention.
Motor 33a is, preferably, a stepping motor and gearbox combination with a power released brake. Such motors are commercially available. When combined with appropriate power, control, and signal circuitry the arrangement can indicate a present telescopic position and automatically go to an operator defined control position and set the brake at that position.
From the foregoing, it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and which are inherent to the apparatus.
It will be understood that certain features and sub-combinations are of utility and may be employed without reference to other features and sub-combinations. This is contemplated by and is within the scope of the claims.
As many possible embodiments may be made of the apparatus of this invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.