US2386494A - Derrick structure - Google Patents

Description

P. R. NAGLE DERRICK STRUCTURE Filed Dec. 5, 1941 3 =muuu!!!mmmum!!!| 2 Sheets-Sheet l Patented Oct. 9, 1945 DERRJCK STRUCTURE Paul R. Nagle, OklahomaCity, Okla. Application .December 5, 1941, Serial No. 421,821 2 claims. (c1. iss- 15) The present invention relates to derrick vstructures and, While in some respects of considerable utility in the'leld of derrick-like structures genrerally,n1ore particularly relates or pertains to an improvement in derrick structures of the type widely used in the oil fields.

The typical oil field derrick comprises a plat- -form which rest-s upon the surface of the ground and a. steel or wooden structure based upon :the platform and rising vertically above it .for a substantial distance.` In the general case; the sur perstructure includes corner vposts or legs and interconnecting bracing members such as tie-rods and`stru'ts, these members functioning to unit-e all portions of the structure into a truss-like column well adapted to withstand wind forces and to support vertical loads. Erection of a derrick of this type has usually been accomplished by following the procedureuniversally used in the erection of ordinary building structures of other types, that is, by placing one building unit or member upon another until a structure of desired height is attained. lCustomarily, the derrick legs are formed in a plurality of individual sections, as are the struts and tie-rods, and broughtto the erection .site vto be there assembled together, such assembly being a rather time-consuming operation and one which'involves a very considerable element of danger. A very substantial number of oil field operatives are killed or injured each year in the erection of such derricks.

In accordance with the present invention an improved derrick structure is provided, and an improved method of erection, the major elements of the structure being assembled together in groups Ybefore being brought to the erection siteV and the several groups of members being there erected in a novel manner. Thus, in accordance with this invention, each of the derrick legs is extensible and contractible, comprising a plurality of telescoping tubes, and the use of bolts or other securing devices for attaching'the various sections of the legs in end-to-end relationship as heretofore generally found necessary is avoided Transportation of the derrick to the well site is facilitated, and the time necessarily consumed in the erection of the derrick in the eld greatly reduced.

It has heretofore been appreciated that telescoping derrick legs might advantageously be employed but no satisfactory mechanism for or method of actually erecting such telescoping legs and securing them in operative position has up until this time been proposed. In accordance with my invention each telescopic leg is, as a step preliminary to the actual erection of the derrick super-structure, pivotally mounted upon a pedestal vwhich fis in turn rigidly supported upon the derrick platform. Simple means is provided, as for instance a rope and winch, for effecting tilting movement of each derriok leg about its horizontal axis of pivotal support in order to swing the telescopic leg into operative position, and' further means is provided to effect a connection between the lower end of the leg as erected and the derrick platform so that the leg is locked in its erected position and at the same time is so supported that its weight, and any vertical ,thrust which may subsequently be imposed upon it, is transmitted directly to the supporting platform instead of being transmitted to the platform through the pedestal. After the telescopic leg has been erected and secured in its operative podescribed in detail.

sition, its inner telescopic sections may be extended by any suitable means and the various necessary lgirts or struts and tie-rods `are positioned. Placement of the bracing members, however, can be readily eiectedand the structure as a whole can be erected in much less time than heretofore, at less expense, and with a greatly reduced element of danger. Likewise, if itis desired to dismantle the -derrick and transfer it to another position the dismantling operation is'greatly facilitated by reason of itsnovel construction.

In the accompanying drawings one form of the vderrick structure is illustrated, and will now be It will be appreciated by those skilled in the art, however, that the embodiment of the invention shown and described is set forth by way of example only.

In the drawings: i

Figure 1 is a side elevation of a derrick einbodying the novel features of the invention, the derr'ick being shown in its `erected or finished and operative position;

Figure 2 is a plan View of the derrick platform showing the derrick legs in the position which theyY occupy just prior to their movement into operative position;

Figure 3 is a section on line 3-3 lof Figure '2;

Figure 14 is a section on line 4-4 `of Figure 3;

Figure 5 is'ra View similar to Figure 3 being a partial section through the derrck platform adjacent one of the leg supporting pedestals, the leg however being shown in operative or erected position, and 1 Figure 6 is a section through the lower end of the outer tubular member of the telescopic leg, showing the means for locking the leg in operative position and transferring its weight to the' the derrick of individual structural elements. At

each corner of the derrick platform is positioned a pedestal II the base flange Il of which is rigidly secured to the platform as by means of bolts I2. The pedestal II may be formed in any suitable way, advantageously being constructed, as shown in the drawings, of two upwardly extending angularly disposed and marginally inter-V connected webs IIZ. Upon the upper end of the pedestal is rigidly secured a bracket I3 having spaced horizontally aligned bearings for a pin I4 which pin likewise projects through a cylindrical aperture in a bracket I5 rigidly secured to the derrick corner post or extensible leg indicated at I6.

Each derrick leg I5, of which there are four,

l'comprises three telescoping tubular sections indicated at Iiia, Mib and I Bc, respectively, the two last mentioned sections being shown in Figures 2 and 3 to be telescoped within the first mentioned or major section Ia, save only for their protruding ends. As shown in Figure 2 the axis of Veach of the pivot pins I4 is disposed at right angles to the axes of the two adjacent pivot pins I4 and as a result each of the four legs I6 of the derrick is disposed at a right angle to each ofv the adjacent legs. Preferably the several legs are angularly disposed with respect to the platform edges, the longitudinal axis of each leg passing, when the leg is in horizontal position, through the vertical axis of the'derrick (i. e. through a vertical line passing through the center of the derrick platform).

As shownV in Figure 3 the derrick leg I6 is in a substantially horizontal position and when occupying such position it may be said to be in an intermediate stage of erection. When rst positioned upon pedestal I I the outer protruding end of the inner telescoping section I6c will normally rest upon the ground surface and the leg thus be disposed at a greater angle to the horizontal than it is shown to have in Figure 3. It is erected with the aid of erecting ropes or cables and a winch or windlass, an erecting rope being indicated at 23 in the drawings. One end of this rope is connected to an annular member or collar 2I rigidly clamped to the outer tubular section Ilia, of the derrick leg at or near that end of this section which will be lower-most after the leg has been locked in operative position. Rope 20 passes over a pulley or guide 22 supported upon a bracket 23 fixed to the associated pedestal II toward the base of such pedestal, and passes further over any other guide, such for instance, as 24, or guides, and thence to a rope winding means which is not illustrated. It will be readily perceived that when the erecting rope is tensioned the lower end of the leg I6 will be drawn downwardly and the entire legrocked about the axis of the pivot I4. Eventually, the derrick leg will be drawn into the position in which it is illustrated in Figure 5, retaining or retarding ropes being employed to restrain the leg from tilting too far after its upper end has passed over the axis of the pin I4 about which it is being tilted.

After having been erected to the position indicated in Figures 1 and 5 the derrick leg must be locked or secured in such position and to accomplish this the securing mechanism shown in Figure 6 is provided. This mechanism includes a socket member 30 rigidly secured to the platform I0, as by bolts 3l, member 30 being provided with a spherical recess or socket 32 in its upper surface. A base casting projecting into and secured to the lower end of the outer section Ia of the tiltable leg is indicated at 33, this base casting being secured in position by bolts 34. It is provided with a threaded axial aperture to receive the exteriorly threaded jack screw 36. The outer end of jack screw 36 is enlarged and provided with cylindrical apertures 31 disposed at right angles to the axis of the screw, and a spherical part or knob 38 adapted to be received within the socket 32 on the socket member 30. A dust cap 39 covers the inner end of the jack screw-receiving recess, as shown, thus preventing the entrance of dust into the threaded recess 35 to cause wear of jack screw.

After a derrick leg has been moved to operative position, the associated jack screw 36 is revolved by bars or implements inserted into apertures 31 and the spherical protuberance 38 caused to move toward and into the socket 32 provided for its reception.. When finally seated, the jack screw locks the associated derrick leg in its operative positionand further than this it elevates the leg slightly so that the weight of the leg is not communicated to the platform through the brackets I3 and I5 and pin I4, but is transmitted directly from the bottom of the leg through the jack screw and socket member to the platform. The mechanism just described is not called upon to resist any substantial amount of lateral thrust after the derrick has been erected, the several legs being interconnected with each other by means of girt or strut members 4B, tie-rods 4I and other securing and bracing members.

In the erection of the derrick the four telescoped corner posts or legs will first be erected by means of the erecting rope 20 and the several jack screws then operated to lock the telescoped legs in position. Following this, the tierods such as 4I connecting suitable brackets fixed ori the outer leg section Ia may be positioned and girts or thrust rods suchl as 40 likewise positioned, thus laterally bracing the legs and preparing the way for further extension. The second. section I6b of each leg or corner post may then be extended and locked in extended position by any suitable means, following which the second series of girts and tie-rods may be applied. This operation is again repeated with respect to the third or innermost leg section I 6c and the derrick then provided with a cap structure and with its full complement of elements required in derrick operation, i. e., the derrickmans platform, suitable block and pulley devices etc., which are not illustrated.

After the derrick has remained as long as it is needed at any position or station, it may be disassembled by reversing the series of erecting operations just described and readily conveyed to some other point, to be again erected as quickly and conveniently as before.

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is:

1. In a derrick, in combination, a platform, a

plurality of vertically elongated pedestals mounted on said platform, a derrick leg pivotally supported, at a point intermediate the ends thereof,

on the upper end of each such pedestal so as to be movable from an inoperative position to a substantially vertical operative position, and means for securing each such leg in operative position,

said means including a socket member on the platform and a socket engaging member adjustably mounted on the leg.

2. In a derrick, in combination, a platform, a plurality of vertically elongated pedestals mounted on said platform, a derrick leg pivotally sup-

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