US3071213A

US3071213A - Derrick centering apparatus

Info

Publication number: US3071213A
Application number: US731748A
Authority: US
Inventors: Emil A Bender
Original assignee: Individual
Current assignee: Individual
Priority date: 1958-04-29
Filing date: 1958-04-29
Publication date: 1963-01-01
Anticipated expiration: 1980-01-01

Description

Jan. 1, 1963 Filed April 29, 1958 E. A. BENDER DERRICK CENTERING APPARATUS 3 Sheets-Sheet l /d x g l 2% w I INVENTOR I 425 ZzzZ4.Zende ATTORNEYS Jan. 1, 1963 E. A. BENDER 3,071,213

DERRICK CENTERING APPARATUS Filed April 29, 1958 3 Sheets-Sheet 2 ATTORNEY;

Jan. 1, 1963 E. A. BENDER DERRICK CENTERING APPARATUS 5 Sheets-Sheet 5 Filed April 29, 1958 ZZZ INV EN TOR JZhiZAJe Maw ATTORNEYS.

ilnited rates Patent @hfice 3,h'il,2l3 Patented Jan. 1, 1%63 3,071,213 DERRECK CENTERHNG APPARATUS Emil A. Bender, R0. Box 52, Bakersfield, Calif. Filed Apr. 29, W58, Ser. No. 731,748 10 Claims. (Cl. 18-l5) The present invention relates generally to the well-drilling art and is more particularly directed to certain new and useful improvements in oil well drilling derricks.

In the well-drilling art, and particularly in the drilling of oil wells which require the utilization of extremely heavy, massive equipment, it is highly important that the drilling derrick, when erected, occupy a substantially vertical position in order to align the traveling block with the center line of the hole to avoid rubbing the side of the rotary table. Furthermore, during the actual drilling operation far greater loads are imposed on the derrick structure and it is thus extremely important that the effective center line of the derrick be positioned as accurately as possible with respect to the center line of the well.

As is well known to those skilled in the art, in the erection of derricks in the past it has been the practice to employ heavy jacks or other lifting devices for the purpose of raising the individual derrick legs so that suitable shims could be inserted or removed to adjust the relative heights of the individual derrick legs and thereby the effective center line of the derrick itself. The use of such equipment in accordance with prior practices is not only difficult, time consuming and dangerous but, in addition, still leaves something to be desired from the standpoint of accuracy in view of the inherent cut and try nature of the process. Of possibly even greater importance is the fact that adjustment of the derrick center line may become necessary while drilling operations are in progress and the use of jacks and shims at such time is practically out of the question whereas shutting down operations for a length of time sufiicient to permit the utilization of jacks and shims may be highly detrimental especially during critical phases of the drilling operation.

In the light of the foregoing, it is a principal object of the present invention to provide novel structure by means of which the individual legs of a well-drilling derrick may be individually adjusted in such manner as to accurately locate the effective center line of the derrick and its traveling block with respect to the center line of the well.

An important object of the invention is to provide apparatus of the type described which avoids the inherent difficulties and dangers of known methods of adjusting the center line of a derrick and which provides for expeditious and easy adjustment not only during erection of the derrick but also at any time during the drilling operations.

Another object of the invention is to provide apparatus of the type described in which the adjustment of the individual derrick legs with respect to the sub-base or supporting base structure is effected through the use of eccentric pin mountings or eccentric hinges permitting relatively fine adjustments to be made.

A further object of the invention is to provide an eccentric hinge mounting for a derrick of the type described including limit stops so arranged as to prevent over center travel of the eccentric portion of the device while at the same time insuring proper original assembly of the eccentric hinge.

An additional object of the invention is to provide an eccentric hinge of the type described including means for positively locking the eccentric hinge pin in various adjusted positions.

Yet another object of the invention is to provide an eccentric hinge of the type described in which the locking means comprises a locking gear including a plurality of teeth each having both a radial face and an inclined face so that the loads on the derrick regs may be transmitted to the supporting base structure through the inclined flat teeth of the locking gear thereby avoiding any load component tending to unlock the mechanism.

A still further object of the invention is to provide apparatus of the type described wherein the eccentric hinge includes a bearing surface curved in more than one plane to permit limited universal pivoting movement.

Another object of the invention is to provide structure of the type described which is both simple and rugged and which may be inexpensively fabricated and require a minimum of maintenance attention in use.

The foregoing together with other and further objects and advantages of the invention will become more readily apparent to those skilled in the art from a consideration of the following detailed specification taken in conjunction with the accompanying figures of drawing in which:

FIGURE 1 is a fragmentary side elevational view, largely schematic, of one form of the derrick illustrating the location of preferred embodiments of eccentric hinge fittings in accordance with the present invention;

FIGURE 2 is a fragmentary end view looking from the right in FIGURE 1 in which parts of the structure are broken away to further illustrate the location of the improved eccentric hinge fittings in accordance with the present invention;

FIGURE 3 is a side elevational view of one of the upper eccentric hinge fittings of FIGURES 1 and 2 shown to a somewhat larger scale but greatly reduced from actual size;

FIGURE 4 is a horizontal transverse cross-sectional view through one of the upper or main eccentric hinge fittings taken substantially along the line d4 of FIG- URE 3;

FIGURE 5 is a vertical transverse cross-sectional View illustrating a detail of the locking bar and guide slot and is taken substantially along the line 5-5 of FIGURE 3;

FIGURE 6 is a fragmentary detailed view of one of the main derrick leg bearings apart from the sub-base structure and with portions of the leg bearing structure broken away to illustrate the interior construction;

FIGURE 7 is a vertical transverse cross-sectional view through the main derrick leg bearing taken substantially along the line '77 of FIGURE 6;

FIGURE 8 is a side elevational view similar to FIG- URE 3 but illustrating one of the lower eccentric hinge fittings as shown in FIGURES 1 and 2; and

FIGURE 9 is a transverse cross-sectional. view through one of the lower eccentric hinge fittings taken substan tially along the line 9-9 of FIGURE 8.

Referring now in somewhat greater detail to the indi vidual figures of the drawing and in particular to FIG- URES l and 2 thereof, eccentric hinges in accordance with the present invention are illustrated in the positions which they would occupy in the well-known type of oil drilling derrick. The complete derrick structure comprises a base or sub-base designated generally by reference numeral 10 provided with a pair of pedestal like structures 12 at its opposite sides to which are pivotally connected the legs 14- of the main derrick body designated generally by reference numeral 16. The structural details of the sub-base it? and main derrick body 16 are not particularly significant so far as the present invention is concerned and it will be understood that suitable braces and girts 18 and 2%) may be provided in the derrick body while vertical posts 22 and diagonal braces 24 serve to interconnect the upper and

lower frames

26 and 28 at opposite sides of the Sub-base 10. The particular derrick selected for the purpose of illustration in the present case also comprises a pair of lifting legs 30 pivotally connected at their lOWer ends to the sub-base lift and provided with rollers or the like 32 at their upper ends which are slidable along tracks provided on the front legs 34 of the derrick body. Derricks of this type are generally referred to as embodying the lever lift principle, the lifting legs 30 being connected by suitable cables 36 and sheaves 38 to the usual traveling block of the derrick (not shown) so that, through operation of the draw works the lifting legs 30 are actuated so that the rollers 32 slide along the front derrick legs 34 to raise the derrick body into operating position at which time the lifting legs 30 are positively locked in any suitable manner as by means of latches designated generally by reference character 41), the lifting legs 39 then becoming integral parts of the derrick while the latter is in operating position.

As indicated above, the principles of the present invention are not limited in their applicability solely to derricks of the type disclosed in FIGURES 1 and 2 of the drawings but may be employed in substantially any known type of derrick construction. However, the derrick illustrated in FIGURES 1 and 2 has been selected for the purpose of explaining the invention since it embodies hinges having useful functions entirely apart from the features of the present invention and, in addition, employs hinges which preferably permit a limited amount of universal pivoting action. Specifically, therefore, as shown in FIGURES 1 and 2, eccentric hinge structures in accordance with the present invention are designated generally by

reference numerals

42 and 44, the hinges 42, or upper hinges, serving to pivotally connect the main derrick body 16 to the sub-base 16 and the lower hinges 44 serving to pivotally connect the lifting legs 30 to the sub-base 10. As will hereinafter become more apparent, the specific structure of the

hinge structures

42 and 44 differs slightly, the upper hinges 42 being illustrated in somewhat greater detail in FIGURES 3 and 4 of the drawings and the lower hinges 44 being similarly illustrated in greater detail in FIGURES 8 and 9 thereof.

Referring now particularly to FIGURES 6 and 7 of the drawings, there is illustrated in somewhat greater detial the construction of the bearing means which is provided at the lower end of the main derrick body. As shown in these views, the lower end of the rear derrick leg 14 is welded or otherwise rigidly secured to a flanged cap piece 46 which in turn is similarly secured to a converging extension 48 of the front derrick leg 34. Transversely of the hinge 42, the cap piece 46 is provided with a pair of depending plates 50-52 which are both spaced laterally of the hinge and also notched as indicated at 54 for a reason to be hereinafter described. Between the plates 50-52, there is provided a solid block 56 which is preferably welded or otherwise secured in any convenient manner to the plates ll52 and also to the cap piece 46. A generally U-shaped member 58 also fits between the plates 5tl'52 and is removably secured to the block 56 in any suitable manner as by means of a bolt 60 and nut 62. The U-shaped member 53 is preferably also shaped in its central portion as indicated by reference numeral 64 in such manner as to provide a bearing surface within which is journaled to stub shaft designated generally by reference numeral 6! which will be hereinafter more fully described. It is to be understood that the specific details of the construction of the bearing means just described are primarily intended to simplify and expedite the initial assembly of the upper hinges 42 prior to raising the main derrick body 16 and the improved eccentric hinge fittings in accordance with the present invention are not to be construed as limited to this specific type of bearing construction.

Referring now particularly to FIGURES 3 and 4 of the drawings, the bearing means which has just been described is illustrated in the position which it occupies when assembled with the mating structure provided on the sub-base it). As shown in these views, the pedestal 12 mounted above the sub-base 16 includes a vertical member 68 having a cap piece 76 welded or otherwise rigidly attached to its top end and may also include suitable gussets or bracing structures 72. Mounted on top of the cap piece 76 in any convenient manner as by welding or the like, is a bearing structure in the form of a clevis comprising transversely spaced plates 74 and 76. Each of the plates 7476 is apertured to provide concentric bearings 78 and 34 in which are journaled the concentric end portions 82 and 84 of the stub shaft 66. The stub shaft 66 is also provided with an eccentric portion 86 which lies between the concentric end portions and the eccentric portion 86 is journaled in the bearing 64 provided at the end of the main derrick body. The stub shaft 66 is also provided with a squared end portion as projecting outward to lie exteriorly of the clevis, by means of which a suitable tool (not shown) may be employed for the purpose of rotating the stub shaft 66. The stub shaft 66 may be held in place within the clevis in any convenient manner as by means of a locking pin 90.

From the description thus far, it will be apparent that rotation of the stub shaft 66 by means of a wrench or other suitable tool in engagement with the squared portion 88 will cause a relative displacement of the bearings in which are journaled the concentric shaft portions 82 84 and the eccentric shaft portion 86 lying therebetween. In order that the stub shaft 86 may be positively retained in various adjusted positions of rotation, a shallow tubular housing $2 is welded or otherwise suitably secured to the outer face of one of the clevis Walls, in this instance the outer wall of the plate 74, and it Will be noted that the housing 92 surrounds a projecting end 32 of the stub shaft 66. A locking gear 94 is securely attached to the projecting end 82 of the stub shaft 66 in any suitable manner as by welding or the like and also lies within the housing 92 being spaced from the outer face of the plate 74 by means of suitable stops or other abutments 96 which are connected to the locking gear 94 but are free to slide over the outer surface of the plate 74. It will thus be understood that the locking gear 94 and stops 96 rotate with the stub shaft 66 within the housing 2 whenever the stub shaft is rotated by engagement of a wrench or suitable tool with the squared portion 88.

Still referring to FIGURES 3 and 4, it will be noted that the interior of the housing 9'2 is provided with a partial ring shaped stop 93 secured to the housing as by welding or the like and an abutment 16% is similarly secured to the outer face of the locking gear 94 in such manner that, as the locking gear 94 rotates with the stub shaft 66, the abutment will rotate in the plane containing the stop 98. It is to be particularly noted, as shown in FIGURE 3, that the locking gear 94 is provided with teeth only over a portion of its periphery, the remainder of the periphery of the locking gear 94 being smooth and of a radius slightly less than the radius of the ring shaped stop 98. However, the toothed portion of the locking gear 94 has a radius somewhat greater than the radius of the stop 98 so that, when the stub shaft 66 and attached locking gear 94 are being a sembled into the positions shown in FIGURES 3 and 4, the angular position of the stub shaft must be as shown in these views since, otherwise, the toothed portion of the locking gear would come into engagement with the stop 98 thereby preventing complete assembly. This is a particularly important feature of the invention since, by reason of this construction, the entire device is rendered substantially foolproof in assembly and, since the stub shaft and locking gear can only be inserted in one position to form a part of the complete hinge, the relative angular positions of the concentric and eccentric portions of the stub shaft 66 are such as to provide an initial centering action so that rotation of the stub shaft 66 in either direction from initial assembly position will be effective to produce maximum displacement of the hinge elements in either direction.

Referring once again to FTGURES 3 and 4- of the drawings, there is illustrated a preferred form of locking means for releasably locking the stub shaft 66 in various positions of adjustment. As illustrated in these views, the locking device comprises an open rectangular guide slot MP2 welded or otherwise suitably secured to the outer wall of the housing 92 and forming an extension of a suitable aperture in the latter located substantially opposite the center of the partial ring shaped stop 98. A locking bar 104 (FIG. 5) also of rectangular shape in cross-section, is slidable within the guide slot Hi2 radially of the locking gear 94. At its inner end, the locking bar 164 is provided with several teeth which are preferably of the same size as the teeth formed on a portion of the periphery of the locking gear 94 and are engageable therewith. A suitable bolt 1% provided with a nut 108 may conveniently be employed for the purpose of securing the locking bar in locking engagement with the locking gear 94. It will also be noted in FIGURE 3 that each of the teeth on the periphery of the locking gear 94 is provided with both a radial and an inclined face so that when the teeth on the locking bar 104 are in engagement with the teeth on the locking gear 94, there will be no component of force transmitted from the derrick body through the eccentric hinge fitting to the locking gear 94 which may tend to disengage the teeth of the locking bar 104 therefrom. In other words, by engagement of the locking bar 1424 with the locking gear 94 along tooth faces which are truly radial, there is no component of force tending to push the locking bar 104 out of engagement.

As mentioned above, the construction of the lower hinges 44- is illustrated in FIGURES 8 and 9 of the drawings. In general, the hinges 4-4 are basically similar to the upper hinges 42 but include additional structure providing for limited universal pivoting movement of the mast or, more accurately, the lifting leg 36 forming a part of the mast. As illustrated in these views, the clevis constituting the fixed portion of the eccentric hinge is provided by plates lid- 112 welded to a base plate 114 formed as an extension of the beam 28 on the subbase 19. The remaining portions of the hinge assembly, including the housing and the locking bar, are substantially identical with the structure of the hinge 42 and have been given the same reference numerals in the drawings. It is to be noted, however, that, for ease of operation, the relative positions of the stop 93, abutment res, and locking bar Mid, have been shifted angularly from the substantially horizontal positions illustrated in FIGURE 3. The operation of these elements is nevertheless exactly the same as in the case of the upper hinges 42.

The principal difference in the construction of the hinges 42 and i4 is best shown in FIGURE 9 wherein it will be noted that the lower end 116 of the lifting leg 3% is provided with an additional bearing surface which is curved in more than one plane as indicated by reference numeral 118. The bearing surface 113 is formed in the interior of a sleeve 129 which, in turn, is held in place within the projecting end 115 of the lifting leg 3% in any suitable manner as by means of a locking ring 122. The bearing 118 journals another sleeve 124- provided with a surface 126 which is also curved in more than one plane and an inner surface 128 within which is journaled the eccentric portion of the stub shaft d6. By reason of the construction just described, the lifting legs 39 are capable of limited universal pivoting movement so that the angular position of each of the lifting legs 3G with respect to the vertical may vary as the main derrick body is being raised into operating position in order to accommodate the relatively diverging tracks formed upon the equally diverging front derrick legs 34. However, once the derrick body has been raised into operating position, the operation of the lower hinges 44 for the purpose of adjusting the effective center line of the derrick with respect to the well is substantially identical to the operation of the upper hinges 42.

While it is believed that the operation of the device will be generally apparent from the description thus far, a brief explanation will be given. Assuming the derrick to be fully assembled and in operating position relative to a well, that is, with the derrick body 16 and sub-base it} in the general positions as illustrated in FIGURES 1 and 2, it will be further assumed that the effective center line of the derrick is out of alignment with the center line of the well either as a result of errors in locating the derrick during erection or as a result of unusual conditions arising during a drilling operation. In order to adjust the effective center line of the derrick with respect to the well, the operator in charge may adjust any or all of the hinges 42-44, the particular hinge or combination thereof to be adjusted being largely a matter of discretion within the judgment and experience of the: operator in charge. It will be understood that due to the fact that the derrick is relatively high as compared to its relatively narrow base, even a slight adjustment of any of the hinges 42- id will produce a greatly magnified displacement of the top of the derrick, which displacement will be reflected directly in the position of the traveling block which hangs from the top of the derrick.

Assuming that the misalignment of the efiective center of the derrick with respect to the weil is of such nature that it can be corrected by simple adjustment of one of the hinges 4,2, the operator will first have a large wrench or equivalent tool attached to the squared end 88 of the stub shaft as So that the latter may be held against accidental displacement. The nut hi may then be removed from the bolt 1% and the latter withdrawn so as to permit the locking bar iii-i to be withdrawn outwardly through the guide slot 102 thereby causing the teeth at the inner end of the locking bar lithito become disengaged from the teeth on the locking gear 94. After this has been done, the operator may cause the stub shaft 66 to be rotated by the tool in engagement with the squared end 88 and, since the concentric shaft portions 82 and 84 are fixed in the bearings 7f53@ formed in the clevis provided by plates 747 secured to the sub-base 1d, the eccentric stub shaft portion 36 will be displaced relative to the concentric portions 32-34 thereby displacing the bearing formed in the elements 5h-52 and 5'8. As a result the derrick leg 14- and entire derrick body 16 will be caused to move upwardly or downwardly depending upon which way the stub shaft 65 is rotated, until the desired position of adjustment of the traveling block has been achieved.

After the stub shaft 66 has been rotated into the desired position of adjustment, the locking bar 1&4 is reinserted through the guide slot Hi2. to cause the teeth at its inner end to engage with a difierent group of teeth on the periphery of the locking gear 94 and the bolt 1&6 is reinserted and held in place by the nut 16 8. Since the abutment 19% rotates in a plane which also contains the stop 98, it will be apparent that rotation of the locking gear 94 and its attached stub shaft 66 is limited by the relative positions of the parts g8 and Mid. This is a par ticular safety feature since, by properly arranging the size and position of these elements, the eccentric portion of the stub shaft 66 can never be rotated to an over center position such as might cause a reversal of the derrick load upon the operating wrench or other tool and thus possible injury to the operators.

In practice, it is deemed preferable to arrange all of the eccentric hinges so that the eccentric portions thereof operate towards the center of the derrick. In this way, the motions of the eccentrics will add to each other laterally and avoid any pushing or pulling stresses on the derrick structure. While this is an important operating feature, the fundamental principle of operation is deemed to be adequately covered by the preceding description of operation of a single eccentric hinge 42.

While there is disclosed herein a preferred embodiment of the invention solely for the purpose of illustration, it will be obvious that numerous modifications, alterations and deviations will occur to those skilled in the art Without departing from the spirit or scope of the invention as defined by the following claims.

I claim:

1. in an oil drilling derrick, a sub-base and a main derrick body having pairs of rear legs and front legs provided with bearings at their lower ends, a plurality of hinges pivotally connecting said legs to said sub-base, each of said hinges comprising a clevis attached to said sub-base and having a pair of concentric bearings formed in its pposite Walls, a stub shaft having concentric end portions journaled in said clevis bearings and an eccentric portion lying therebetween and journaled in said leg bearings, means on said stub shaft exterior-1y of said clevis for rotating said stub shaft, a shallow tubular housing attached to the outer face of one of said clevis Walls and surrounding a projecting end of said stub shaft, a toothed locking gear attached to said stub shaft Within said housing, a partial ring shaped stop attached to the interior of said housing, an abutment attached to the outer face of said gear for engagement with said stop, said gear having a portion of its periphery smooth and of a radius less than that of said ring shaped stop and the teeth covering the remainder of the periphery of said gear having a radius greater than that of said stop and each having a radial face and an inclined face, means forming an open rectangular guide slot in said housing opposite said stop, a locking bar slidable in said slot radially of said gear and having teeth at its inner end engageable with the teeth of said gear, and a bolt engageable with the Walls of said slot and said bar for holding the latter in locking engagement with said gear.

2. In a derrick, a sub-base and a main derrick body provided with bearing means at its lower end, hinge means pivotally connecting said derrick body to said sub-base comprising a clevis attached to said sub-base and having a pair of concentric bearings formed in its opposite Walls, a stub shaft having concentric end portions journaled in said clevis bearings and an eccentric portion lying therebetween and journaled in said bearing means, means on said stub shaft exteriorly of said clevis for rotating said stub shaft, a shallow tubular housing attached to the outer face of one of said clevis Walls and surrounding a projecting end of said stub shaft, a toothed locking gear attached to said stub shaft within said housing, a partial ring shaped stop attached to the interior of said housing, an abutment attached to the outer face of said gear for engagement with said stop, said gear having a portion of its periphery smooth and of a radius less than that of said ring shaped stop and the teeth covering the remainder of the periphery of said gear having a radius greater than that of said stop and each having a radial face and an inclined face, means forming an open rectangular guide slot in said housing opposite said stop, a locking bar slidable in said slot radially of said gear and having teeth at its inner end engageable with the teeth of said gear, and a bolt engagea le With the Walls of said slot and said bar for holding the latter in locking engagement with said gear.

3. In a derrick, a sub-base and a main derrick body, hinge means pivotally connecting said derrick body to said sub-base comprising bearing means on said sub-base and said derrick body, respectively, a stub shaft having a portion journaled in said sub-base bearing means and an eccentric portion journaled in said derrick body bearing means, means on said stub shaft for rotating said stub shaft, a housing attached to said sub-base bearing means and surrounding a projecting end of said stub shaft, a toothed locking gear attached to said stub shaft Within said housing, a partial ring shaped stop attached to the interior of said housing, an abutment attached to the outer face of said gear for engagement with said stop, said gear having a portion of its periphery smooth and of a radius less than that of said ring shaped stop and the teeth covering the remainder of the periphery of said gear having a radius greater than that of said stop and each having a radial face and an inclined face, means forming an open rectangular guide slot in said housing opposite said stop, a locking bar slidable in said slot radially of said gear and having teeth at its inner end engageable with the teeth of said gear, and a bolt engageable With the walls of said slot and said bar for holding the latter in locking engagement with said gear.

4. In a derrick, a sub-base and a main derrick body, hinge means pivotally connecting said derrick body to said sub-base comprising bearing means on said sub-base and said derrick body, respectively, a stub shaf having a portion journaled in said sub-base bearing means and an eccentric portion journaled in said derrick body bearing means, means for rotating said stub shaft, a housing attached to said sub-base bearing means and surrounding a projecting end of said stub shaft, a toothed locking gear attached to said stub shaft Within said housing, a partial ring shaped stop attached to the interior of said housing, an abutment attached to said gear for engagement with said stop, said gear having a portion of its periphery smooth and of a radius less than that of said ring shaped stop and the'teeth covering the remainder of the periphery of said gear having a radius greater than that of said stop and each having a radial face and an inclined face, means forming a guide slot in said housing, a locking bar slidable in said slot radially of said gear and having teeth at its inner end eugageable w th the teeth of said gear, and means for holding said bar in locking engagement with said gear.

5. In a derrick, a base and a mast, hinge means pivotally connecting said mast to said base comprising bearing means on said base and said mast, respectively, a stub shaft having a portion journaled in said base bearing and an eccentric portion journaled in said mast bearing means, means for rotating said stub shaft, a housing on said base surrounding a projecting end of said stub shaft, 2. locking gear attached to said stub shaft within said housing, said gear having a plurality of teeth each provided with a radial face and an inclined face, means forming a guide slot in said housing, a locking bar slidable in said slot radially of said gear and having teeth at its inner end engageable with the teeth of said gear, and means for holding said bar in locking engagement with said gear.

6. In a derrick, a base and a mast, hinge means pivotally connecting said mast to said base comprising bearing means on said base and said mast, respectively, a stub shaft having a portion journaled in said base bearing means and an eccentric portion journaled in said mast bearing means, means for rotating said stub shaft, a housing on said base surrounding a projecting end of said stub shaft, a locking gear attached to said stub shaft Within said housing, said gear having a plurality of teeth each provided With a radial face an an inclined face, means forming a guide slot in said housing, and a locking bar slidable in said slot radially of said gear and having teeth at its inner end engageable with the teeth of said gear.

7. In a derrick, a base and a mast, hinge means pivotally connecting said mast to said base comprising bearing means on said base and said mast, respectively, a stub shaft having a portion journaled in said base bearing means and an eccentric portion journaled in said mast bearing means, means for rotating said stub shaft, a housing on said base surrounding a projectin end of said stub shaft, a locking gear attached to said stub shaft Within said housing and having a plurality of teeth, means forming a guide slot in said housing, and a locking bar slidable in said slot radially of said gear and having teeth at its inner end engageable with the teeth of said gear.

8. In a derrick, a base and a mast, hinge means pivotally connecting said mast to said base comprising bearing means on said base and said mast, respectively, a stub shaft having a portion journaled in said base bearing means and an eccentric portion journaled in said mast bearing means, means for rotating said stub shaft, a locking gear attached to said stub shaft and having a plurality of teeth, and a locking bar slidable radially of said gear and having teeth at its inner end engageable with the teeth of said gear.

9. In a derrick, a base and a mast, hinge means pivotally connecting said mast to said base comprising bearing means on said base and said mast, respectively, a stub shaft having a portion journaled in said base bearing means and an eccentric portion journaled in said mast bearing means, means for rotating said stub shaft to adjust the relative positions of said mast and said base, and means for releasably locking said stub shaft in various positions for adjustment, said mast bearing means including a first bearing surrounding the eccentric portion of said stub shaft, and a second bearing concentric with said first bearing and provided with a bearing surface curved in more than one plane whereby said mast is capable of limited universal pivoting movement.

10. In a derrick, a base and a mast, hinge means pivotally connecting said mast to said base comprising bearing 5 means on said base and said mast, respectively, a stub shaft having a portion journaled in said base bearing means and an eccentric portion jonrnaled in said mast bearing means, means for rotating said stub shaft to adjust the relative positions of said mast and said base, and 10 means for releaseably locking said stub shaft in various positions for adjustment, said mast bearing means including a bearing surface curved in more than one plane whereby said mast is capable of limited universal pivoting movement.

References Cited in the file of this patent UNITED STATES PATENTS

Claims

1. IN AN OIL DRILLING DERRICK, A SUB-BASE AND A MAIN DERRICK BODY HAVING PAIRS OF REAR LEGS AND FRONT LEGS PROVIDED WITH BEARINGS AT THEIR LOWER ENDS, A PLURALITY OF HINGES PIVOTALLY CONNECTING SAID LEGS TO SAID SUB-BASE, EACH OF SAID HINGES COMPRISING A CLEVIS ATTACHED TO SAID SUB-BASE AND HAVING A PAIR OF CONCENTRIC BEARINGS FORMED IN ITS OPPOSITE WALLS, A STUB SHAFT HAVING CONCENTRIC END PORTIONS JOURNALED IN SAID CLEVIS BEARINGS AND AN ECCENTRIC PORTION LYING THEREBETWEEN AND JOURNALED IN SAID LEG BEARINGS, MEANS ON SAID STUB SHAFT, A HOLLOW TUBULAR HOUSING ATTACHED TO THE OUTER FACE OF ONE OF SAID CLEVIS WALLS AND SURROUNDING A PROJECTING END OF SAID STUB SHAFT, A TOOTHED LOCKING GEAR ATTACHED TO SAID STUB SHAFT WITHIN SAID HOUSING, A PARTIAL RING SHAPED STOP ATTACHED TO THE INTERIOR OF SAID HOUSING, AN ABUTMENT ATTACHED TO THE OUTER FACE OF SAID GEAR FOR ENGAGEMENT WITH SAID STOP, SAID GEAR HAVING A PORTION OF ITS PERIPHERY SMOOTH AND OF A RADIUS LESS THAN THAT OF SAID RING SHAPED STOP AND THE TEETH COVERING THE REMAINDER OF THE PERIPHERY OF SAID GEAR HAVING A RADIUS GREATER THAN THAT OF SAID STOP AND EACH HAVING A RADIAL FACE AND AN INCLINED FACE, MEANS FORMING AN OPEN RECTANGULAR GUIDE SLOT IN SAID HOUSING OPPOSITE SAID STOP, A LOCKING BAR SLIDABLE IN SAID SLOT RADIALLY OF SAID GEAR AND HAVING TEETH AT ITS INNER END ENGAGEABLE WITH THE TEETH OF SAID GEAR, AND A BOLT ENGAGEABLE WITH THE WALLS OF SAID SLOT AND SAID BAR FOR HOLDING THE LATTER IN LOCKING ENGAGEMENT WITH SAID GEAR.