Patent Abstract:
The present invention discloses a high-capacity drilling rig system that includes novel design features that alone and more particularly in combination facilitate a fast rig-up and rig-down with a single set of raising cylinders and maintains transportability features. In particular, a transport trailer is disclosed having a first support member and a drive member which align the lower mast portion with inclined rig floor ramps and translate the lower mast legs up the ramps and into alignment for connection. A pair of wing brackets is pivotally deployed from within the lower mast width for connection to the raising cylinder for raising the mast from a horizontal position into a vertical position. A cantilever is pivotally deployed from beneath the rig floor to a position above it for connection to the raising cylinder for raising the substructure from a collapsed position into the erect position.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional of U.S. patent application Ser. No. 13/335,749, now U.S. Pat. No. 9,027,287, and claims the benefit of priority to Provisional Patent Application No. 61/428,778 filed Dec. 30, 2010. 
    
    
     TECHNICAL FIELD OF INVENTION 
     The present invention relates to a new rig mast, substructure, and transport trailer for use in subterranean exploration. The present invention provides rapid rig-up, rig-down and transport of a full-size drilling rig. In particular, the invention relates to a self-erecting drilling rig in which rig-up of the mast and substructure may be performed without the assistance of a crane. The rig components transport without removal of the drilling equipment including top drive with mud hose and electrical service loop, AC drawworks, rotary table, torque wrench, standpipe manifold, and blow out preventers (BOP), thus reducing rig-up time and equipment handling damage. 
     BACKGROUND OF THE INVENTION 
     In the exploration of oil, gas and geothermal energy, drilling operations are used to create boreholes, or wells, in the earth. Drilling rigs used in subterranean exploration must be transported to the locations where drilling activity is to be commenced. These locations are often remotely located. The transportation of such rigs on state highways requires compliance with highway safety laws and clearance underneath bridges or inside tunnels. This requirement results in extensive disassembly of full-size drilling rigs to maintain a maximum transportable width and transportable height (mast depth) with further restrictions on maximum weight, number and spacing of axles, and overall load length and turning radius. These transportation constraints vary from state to state, as well as with terrain limitations. These constraints can limit the size and capacity of rigs that can be transported and used, conflicting with the subterranean requirements to drill deeper, or longer reach horizontal wells, more quickly, requiring larger rigs. 
     Larger, higher capacity drilling rigs are needed for deeper (or horizontally longer) drilling operations, since the hook load for deeper operations is very high, requiring rigs to have a capacity of 500,000 lbs. and higher. Constructing longer, deeper wells requires increased torque, mud pump capacity and the use of larger diameter tubulars in longer strings. Larger equipment is required to handle these larger tubulars and longer strings. All of these considerations drive the demand for larger rigs. Larger rigs require a wider base structure for strength and wind stability, and this requirement conflicts with the transportability constraint and the time and cost of moving them. Larger rigs also require higher drill floors to accommodate taller BOP stacks. Once transported to the desired location, the large rig components must each be moved from a transport trailer into engagement with the other components located on the drilling pad. Moving a full-size rig and erecting a conventional mast and substructure generally requires the assistance of large cranes at the drilling site. The cranes will be required again when the exploration activity is complete and it is time to take the rig down and prepare it for transportation to a new drilling site. 
     Once the cranes have erected the mast and substructure, it is necessary to reinstall much of the machinery associated with the operation of the drilling rig. Such machinery includes, for example, the top drive with mud hose and electrical service loop, AC drawworks, rotary table, torque wrench, standpipe manifold, and BOP. 
     Rigs have been developed with mast raising hydraulic cylinders and with secondary substructure raising cylinders for erection of the drilling rig without the use, or with minimal use, of cranes. For example, boost cylinders have been used to fully or partially raise the substructure in combination with mast raising cylinders. These rigs have reduced rig transport and rig-up time; however, substructure hydraulics are still required and the three-step lifting process and lower mast lifting capacity remain compromised in these configurations. Also, these designs incorporate secondary lifting structures, such as mast starter legs which are separated completely from the mast for transportation. These add to rig-up and rig-down time, weight, and transportation requirements, encumber rig floor access, and may still require cranes for rig-up. Importantly, the total weight is a critical concern. 
     Movement of rig masts from transport trailers to engagement with substructures remains time consuming and difficult. Also, rig lifting supports create a wider mast profile, which limits the size of the structure support itself due to transportation regulations, and thus the wind load limit of the drilling rig. In particular, it is very advantageous to provide substructures having a height of less than 8 (eight) feet to minimize the incline and difficulty of moving the mast from its transport position into its connectable position on top of the collapsed substructure. However, limiting the height of the collapsed substructure restricts the overall length of retracted raising cylinders in conventional systems. It further increases the lift capacity requirement of the raising cylinder due to the disadvantageous angle created by the short distance from ground to drilling floor in the collapsed position. 
     For the purpose of optimizing the economics of the drilling operation, it is highly desirable to maximize the structural load capacity of the drilling rig and wind resistance without compromising the transportability of the rig, including, in particular, the width of the lower mast section, which bears the greatest load. 
     Assembly of drilling rigs for different depth ratings results in drilling rig designs that have different heights. Conventional systems often require the use of different raising cylinders that are incorporated in systems that are modified to accommodate the different capacity and extension requirements that are associated with drilling rigs having different heights from ground to drill floor. This increases design and construction costs, as well as the problems associated with maintaining inventories of the expensive raising cylinders in multiple sizes. 
     It is also highly desirable to devise a method for removing an equipment-laden lower mast section from a transport trailer into engagement with a substructure without the use of supplemental cranes. It is also desirable to minimize accessory hydraulics, and the size and number of telescopic hydraulic cylinders required for rig erection. It is also desirable to minimize accessory structure and equipment, particularly structure and equipment that may interfere with transportation or with manpower movement and access to the rig floor during drilling operations. It is also desirable to ergonomically limit the manpower interactions with rig components during rig-up for cost, safety and convenience. 
     It is also highly desirable to transport a drilling rig without unnecessary removal of any more drilling equipment than necessary, such as the top drive with mud hose and electrical service loop, AC drawworks, rotary table, torque wrench, standpipe manifold, and BOP. It is highly desirable to transport a drilling rig without removing the drill line normally reeved between the travelling block and the crown block. It is also highly desirable to remove the mast from the transport trailer in alignment with the substructure, and without the use of cranes. It is also desirable to maintain a low height of the collapsed substructure. It is also desirable to have a system that can adapt a single set of raising cylinders for use on substructures having different heights. 
     Technological and economic barriers have prevented the development of a drilling rig capable of achieving these goals. Conventional prior art drilling rig configurations remain manpower and equipment intensive to transport and rig-up. Alternative designs have failed to meet the economic and reliability requirements necessary to achieve commercial application. In particular, in deeper drilling environments, high-capacity drilling rigs are needed, such as rigs having hook loads in excess of 500,000 lbs., and with rated wind speeds in excess of 100 mph. Quick rig-down and transportation of these rigs have proven to be particularly difficult. Highway transport regulations limit the width and height of the transported mast sections as well as restricting the weight. In many states, the present width and height limit is 14 feet by 14 feet. Larger loads are subject to additional regulations including the requirement of an escort vehicle. 
     In summary, the preferred embodiments of the present invention provide unique solutions to many of the problems arising from a series of overlapping design constraints, including transportation limitations, rig-up limitations, hydraulic raising cylinder optimization, craneless rig-up and rig-down, and static hook load and rated wind speed requirements. 
     SUMMARY OF THE INVENTION 
     The present invention provides a substantially improved drilling rig system. In one embodiment, a drilling mast transport skid is provided comprising a frame positionable on a transport trailer. A forward hydraulically actuated slider, and a rear hydraulically actuated slider are located on the frame. The sliders are movable in perpendicular relationship to the frame. An elevator is movably located between the rear slider and the mast supports (or equivalently between the rear slider and frame) for vertically elevating the mast relative to the frame. A carriage is movably located between the frame and the forward slider for translating the forward slider along the length of the frame. A mast section of a drilling rig may be positioned on the sliders, such that controlled movement of the sliders, the elevator and the carriage can be used to position the mast section for connection to another structure. 
     In another embodiment, a slide pad is located on an upper surface of at least one of the sliders, so as to permit relative movement between the mast section and the slider when articulating the slider. 
     In another embodiment, an elevator is located on each side of the rearward slider, between the rearward slider and the mast support, such that each elevator is independently movable between a raised and lowered position for precise axial positioning of the mast section. 
     In another embodiment, a roller set between the carriage and the frame provides a rolling relationship between the carriage and the frame. A motor is connected to the carriage. A pinion gear is connected to the motor. A rack gear is mounted lengthwise on the frame, and engages the pinion gear, such that operation of the motor causes movement of the forward slider lengthwise along the frame. 
     In one embodiment, a drilling rig is provided, comprising a collapsible substructure including a base box, a drill floor and a pair of raising cylinders pivotally connected at one end to the base box and having an opposite articulating end. The raising cylinders are selectively extendable relative to their pivotal connection at the base box. A mast is provided, and has a lower mast section comprising a framework having a plurality of cross-members that define a transportable width of the lower mast section. The lower mast section has a plurality of legs, having an upper end attached to the framework, and an opposite lower end. A connection on the lower end of at least two legs is provided for pivotally connecting the lower mast section to the drill floor. 
     A pair of wing brackets is deployably secured to the lower mast section framework. The wing brackets are pivotal or slidable between a stowed position within the transport width of the lower mast section and a deployed position that extends beyond the transport width of the lower mast section. The raising cylinder is connectable to the wing brackets and extendable to rotate the lower mast section from a generally horizontal position to a raised position above the drill floor to a substantially vertical position above the drill floor, or to a desired angle that is less than vertical. 
     In another embodiment, each wing bracket of the drilling rig further comprises a frame having a pair of frame sockets on its opposite ends. The frame sockets pivotally connect the frame to the lower mast section. The wing brackets pivot to fit substantially within a portal in the lower mast section in the stowed position. 
     In another embodiment, the pivotal connection of the frame to the mast defines a pivot axis of the wing bracket about which the wing bracket is deployed and stowed. The pivotal connection between the lower mast section legs and the drill floor defines a pivot axis of the mast. In a preferred embodiment, the pivot axis of the wing bracket is substantially perpendicular to the pivot axis of the mast. 
     In another embodiment, each wing bracket of the drilling rig further comprises a frame and an arm extending from the frame towards the interior of the lower mast section. An arm socket is located on the end of the arm opposite to the frame. A bracket locking pin is attached to the lower mast section and is extendable through the arm socket to lock the wing bracket in the deployed position. 
     In another embodiment, each wing bracket of the drilling rig further comprises a frame and a lug box attached to the frame. The lug box is receivable of the articulating end of the raising cylinder. A lug socket is located on the lug box. A raising cylinder lock pin is extendable through the articulating end of the raising cylinder and the lug socket to lock the raising cylinder in pivotal engagement with the wing bracket. 
     In another embodiment, each wing bracket of the drilling rig further comprises a wing cylinder attached between the interior of the lower mast section and the arm of the wing bracket. Actuation of the wing cylinder moves the wing bracket between the deployed and stowed positions, without the need to have workers scaling the mast to lock the wing in position. 
     In one embodiment, a drilling rig assembly is provided comprising a collapsible substructure that is movable between the stowed and deployed positions. The collapsible substructure includes a base box, a drill floor framework and a drill floor above the drill floor framework, and a plurality of legs having ends pivotally connected between the base box and the drill floor. The legs support the drill floor above the base box in the deployed position. A raising cylinder has a lower end pivotally connected at one end to the base box and an opposite articulating end. The raising cylinder is selectively extendable relative to the pivotal connection at the base box. A cantilever is provided, having a lower end and an upper end, and being pivotally connected to the drill floor framework, the upper end movable between a stowed position below the drill floor and a deployed position above the drill floor. The upper end of the cantilever is connectable to the articulating end of the raising cylinder when the cantilever is in the deployed position, such that extension of the raising cylinder raises the substructure into the deployed position. 
     In one embodiment, the raising cylinder can be selectively connected to a lower mast section of a drilling mast that is pivotally connected above the drill floor such that extension of the raising cylinder raises the lower mast section from a generally horizontal position to a generally vertical position above the drill floor. In another embodiment, the raising cylinder raises the lower mast section from a generally horizontal position to a position above the drill floor that is within 50 degrees of vertical to permit slant drilling operations. 
     In another embodiment, a cantilever cylinder is pivotally connected at one end to the drill floor framework and has an opposite end pivotally connected to the cantilever. The cantilever cylinder is selectively extendable relative to its pivotal connection at the drill floor framework. Extension of the cantilever cylinder rotates the cantilever from the stowed position below the drill floor to the deployed position above the drill floor. Refraction of the cantilever cylinder refracts the cantilever from the deployed position above the drill floor to the stowed position below the drill floor. 
     In another embodiment, the substructure includes a box beam extended horizontally beneath the drill floor and a beam brace affixed to the box beam. The cantilever engages the beam brace upon rotation of the cantilever into the fully deployed position. Extension of the raising cylinder transfers the lifting force for deployment of the substructure to the box beam through the cantilever and beam brace. 
     In another embodiment, when the substructure is in the collapsed position and the raise cylinder is connected to the cantilever, the centerline of the raise cylinder forms an angle to the centerline of a substructure leg that is greater than 20 degrees. In another embodiment, when the substructure is in the collapsed position, the distance from the ground to the drill floor is less than 8 feet. 
     In another embodiment, connection of the upper end of the cantilever to the articulating end of the raising cylinder forms an angle between the cantilever and the raising cylinder of between 70 and 100 degrees, and extension of the raising cylinder to deploy the substructure reduces the angle between the cantilever and the raising cylinder to between 35 and 5 degrees. 
     In another embodiment, an opening is provided in the drill floor that is sufficiently large so as to permit passage of the cantilever as it moves between the stowed and deployed positions. A backer panel is attached to the cantilever and is sized for complementary fit into the opening of the drill floor when the cantilever is in the stowed position. 
     In another embodiment, the mast has front legs and rear legs. The front legs are connectable to front leg shoes located on the drill floor. The rear legs are connectable to rear leg shoes located on the drill floor. In another embodiment, the lower end of the raising cylinder is pivotally connected to the base box at a location beneath and between the front leg shoes and the rear leg shoes of the drill floor of the erected substructure. The lower end of the cantilever is pivotally connected to the drill floor framework at a location beneath the drill floor. 
     In one embodiment, a drilling rig assembly is provided, comprising a collapsible substructure movable between the stowed and deployed positions. The collapsible substructure includes a base box and a drill floor framework having a drill floor above the drill floor framework. The substructure further includes a plurality of legs having ends pivotally connected to the base box and drill floor framework, such that the legs support the drill floor above the base box in the deployed position of the substructure. A mast is included, having a lower mast section pivotally connected above the drill floor and movable between a generally horizontal position to a position above the drill floor. 
     A cantilever has a lower end and an upper end, the lower end being pivotally connected to the drill floor framework. The upper end is movable between a stowed position below the drill floor and a deployed position above the drill floor. A raising cylinder is pivotally connected at one end to the base box and has an opposite articulating end. The raising cylinder is selectively extendable relative to the pivotal connection at the base box. The articulating end of the raising cylinder is connectable to the mast such that extension of the raising cylinder moves the mast from a generally horizontal position above the drill floor to a generally vertical position above the drill floor. The articulating end of the raising cylinder is also connectable to the upper end of the cantilever such that extension of the raising cylinder raises the drilling substructure into the deployed position. 
     In another embodiment, the raising cylinder can be selectively connected to a lower mast section of a drilling mast that is pivotally connected above the drill floor such that extension of the raising cylinder raises the lower mast section from a generally horizontal position to a generally vertical position above the drill floor. In another embodiment, the partial extension of the raising cylinder is selectable for raising the mast to an angular position of at least 50 degrees of the vertical for slant drilling operations. 
     In another embodiment, a pair of wing brackets is pivotally attached to the lower mast section and capable of attachment to the raising cylinder. The raising cylinder may be connected to the wing brackets and extended to rotate the lower mast section from a generally horizontal position to a generally vertical position above the drill floor. In another embodiment, the partial extension of the raising cylinder is selectable for raising the mast to an angular position of at least 50 degrees of the vertical for slant drilling operations. 
     In another embodiment, the wing brackets are pivotal between a deployed position and a stowed position. A lug socket is located on each bracket and is connectable to the raising cylinder. In the stowed position, the wing brackets are contained within the width of the lower mast section. In the deployed position, the wing brackets extend beyond the width of the lower mast such that the sockets are in alignment with the articulating end of the raising cylinder. 
     In one embodiment, a drilling rig assembly is provided comprising a raising cylinder. The raising cylinder has a first angular position for connection to a deployable wing bracket connected to a mast section. The raising cylinder has a second angular position for detachment from the deployable wing bracket at the conclusion of raising a mast into the vertical position. The raising cylinder has a third angular position for connection to a retractable cantilever connected to a substructure in a stowed (collapsed) position. The raising cylinder has a fourth angular position for detachment of the raising cylinder from the retractable cantilever at the conclusion of raising a subsection into the deployed (vertical) position. In a preferred embodiment, the first angular position is located within 10 degrees of the fourth angular position, and the second angular position is located within 10 degrees of the third angular position. 
     In another embodiment, the raising cylinder has a pivotally connected end about which it rotates and an articulating end for connection to the deployable wing bracket and the retractable cantilever. The articulating end of the raising cylinder forms a first lifting arc between the first angular position and the second angular position. The articulating end of the raising cylinder forms a second lifting arc between the first angular position and the second angular position. The first and second lifting arcs intersect substantially above the pivotally connected end of the raising cylinder. 
     In another embodiment, the raising cylinder rotates in a first rotational direction while raising the mast sections. The raising cylinder rotates in a second rotational direction opposite to the first rotational direction while raising the substructure. 
     In another embodiment, the raising cylinder is a multi-stage cylinder having a maximum of three stages. In another embodiment, the wing brackets are deployed about a first pivot axis. The cantilevers are deployed about a second pivot axis that is substantially perpendicular to the first pivot axis. 
     In one embodiment, a drilling rig assembly is provided comprising a collapsible substructure movable between the stowed and deployed positions. The collapsible substructure includes a base box and a drill floor framework with a drill floor above the drill floor framework. A plurality of substructure legs have ends pivotally connected to the base box and the drill floor for supporting the drill floor above the base box in the deployed position. 
     A lower mast section of a drilling mast is provided comprising a lower section framework having a plurality of cross-members that define a transportable width of the lower mast section. A plurality of legs is pivotally connected to the lower section framework for movement between a stowed position and a deployed position. A connection is provided on the lower end of at least two legs for pivotally connecting the lower mast section above the drill floor. 
     A raising cylinder is pivotally connected at one end to the base box and has an opposite articulating end. The raising cylinder is selectively extendable relative to the pivotal connection at the base box. A wing bracket is pivotally connected to the lower mast section of a drilling mast and movable between a stowed position and a deployed position. The wing bracket is connectable to the articulating end of the raising cylinder when the cantilever is in the deployed position, such that extension of the raising cylinder raises the lower mast section into a generally vertical position above the drill floor. 
     In another embodiment, the legs are movable between a stowed position within the transport width and a deployed position external of the transport width. The wing brackets are also movable between a stowed position within the transport width and a deployed position external of the transport width. 
     In another embodiment, the legs are pivotally movable about a first axis. The wing brackets are pivotally movable about a second axis that is substantially perpendicular to the first axis. 
     In another embodiment, a cantilever is pivotally connected to the drill floor and is movable between a stowed position below the drill floor and a deployed position above the drill floor. The cantilever is connectable to the articulating end of the raising cylinder when the cantilever is in the deployed position, such that extension of the raising cylinder raises the drill floor into the deployed position. 
     In another embodiment, the cantilever is deployed about a third pivot axis substantially perpendicular to each of the first pivot axis and the second pivot axis. 
     In one embodiment, a method of assembling a drilling rig provides for steps comprising: setting a collapsible substructure onto a drilling site; moving a lower mast section into proximity with the substructure; pivotally attaching the lower mast section to a drill floor of the substructure; pivotally deploying a pair of wings outward from a stowed position within the lower mast section to a deployed position external of the lower mast section; connecting an articulating end of a raising cylinder having an opposite lower end to the substructure to each wing; extending the raising cylinder so as to rotate the lower mast section from a substantially horizontal position to an erect position above the drill floor; pivotally deploying a pair of cantilevers upward from a stowed position beneath the drill floor to a deployed position above the drill floor; connecting the articulating end of the raising cylinder to each deployed cantilever; and extending the raising cylinder so as to lift the substructure from a stowed, collapsed position to a deployed, erect position. 
     In another embodiment, the raising cylinders are adjusted as a central mast section and an upper mast section are sequentially attached to the lower mast section. 
     As will be understood by one of ordinary skill in the art, the sequence of the steps disclosed may be modified and the same advantageous result obtained. For example, the wings may be deployed before connecting the lower mast section to the drill floor (or drill floor framework). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The objects and features of the invention will become more readily understood from the following detailed description and appended claims when read in conjunction with the accompanying drawings in which like numerals represent like elements. 
       The drawings constitute a part of this specification and include exemplary embodiments to the invention, which may be embodied in various forms. It is to be understood that in some instances various aspects of the invention may be shown exaggerated or enlarged to facilitate an understanding of the invention. 
         FIG. 1  is an isometric view of a drilling system having certain features in accordance with the present invention. 
         FIG. 2  is an isometric exploded view of a mast transport skid having certain features in accordance with the present invention. 
         FIG. 3  is an isometric view of the mast transport skid of  FIG. 2 , illustrated assembled. 
         FIG. 4  is an isometric view of a first stage of the rig-up sequence for a drilling system, as performed in accordance with the present invention. 
         FIG. 5  is an isometric view of a second stage of the rig-up sequence for a drilling system, as performed in accordance with the present invention. 
         FIG. 6  is an isometric view of a third stage of the rig-up sequence for a drilling system, as performed in accordance with the present invention. 
         FIG. 7  is an isometric view of a fourth stage of the rig-up sequence for a drilling system, as performed in accordance with the present invention. 
         FIG. 8  is an isometric view of the wing bracket illustrated in accordance with an embodiment of the present invention. 
         FIG. 9  is an isometric view of the wing bracket of  FIG. 8 , illustrated in the deployed position relative to a lower mast section. 
         FIGS. 10, 11 and 12  are side views illustrating a fifth, sixth and seventh stage of the rig-up sequence for a drilling system, as performed in accordance with the present invention. 
         FIG. 13  is a side view of an eighth stage of the rig-up sequence for a drilling system, as performed in accordance with the present invention. 
         FIG. 14  is a side view of a ninth stage of the rig-up sequence for a drilling system, as performed in accordance with the present invention. 
         FIG. 15  is an isometric view of a retractable cantilever, shown in accordance with the present invention. 
         FIG. 16  is a side view of a tenth stage of the rig-up sequence for a drilling system, as performed in accordance with the present invention. 
         FIG. 17  is a side view of an eleventh stage of the rig-up sequence for a drilling system, as performed in accordance with the present invention. 
         FIG. 18  is a side view of a twelfth stage of the rig-up sequence for a drilling system, as performed in accordance with the present invention. 
         FIG. 19  is a side view of a thirteenth stage of the rig-up sequence for a drilling system, as performed in accordance with the present invention. 
         FIG. 20  is a diagram of the relationships between the mast and substructure raising components of the present invention. 
         FIG. 21  is a diagram of certain relationships between the raising cylinder, the deployable cantilever, and the substructure of the present invention. 
         FIG. 22  is a diagram of drilling rig assemblies of three different sizes, each using the same raising cylinder pair in combination with the deployable cantilever and deployable wing bracket. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following description is presented to enable any person skilled in the art to make and use the invention, and is provided in the context of a particular application and its requirements. Various modifications to the disclosed embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein. 
       FIG. 1  is an isometric view of a drilling rig assembly  100  including features of the invention. As seen in  FIG. 1 , drilling assembly  100  has a lower mast section  220  mounted on top of a substructure  300 . 
     Mast leg pairs  230  are pivotally attached to lower mast section  220  at pivot connections  226 . Mast leg cylinders  238  may be connected between lower mast section  220  and mast legs  230  for moving mast legs  230  between a transportable stowed position and the illustrated deployed position. The wider configuration of deployed mast legs  230  provides greater drilling mast wind resistance and more space on a drilling floor for conducting drilling operations. 
     A pair of wing brackets  250  is pivotally connected to lower mast section  220  immediately above pivot connections  226 . Wing brackets  250  are movable between a transportable stowed position and the illustrated deployed position. 
     Collapsible substructure  300  supports mast sections  200 ,  210  (not shown) and  220 . Substructure  300  includes a base box  310  located at ground level. A drill floor framework  320  is typically comprised of a pair of side boxes  322  and a center section  324 . A plurality of substructure legs  340  is pivotally connected between drill floor framework  320  and the base box  310 . A box beam  326  (not visible) spans side boxes  322  of drill floor framework  320  for structural support. A drill floor  330  covers the upper surface of drill floor framework  320 . 
     A pair of cantilevers  500  is pivotally attached to drill floor framework  320 . Cantilevers  500  are movable between a transportable stowed position and a deployed position. In the stowed position, cantilevers  500  are located beneath drill floor  330 . In the deployed position, cantilevers  500  are raised above drill floor  330 . 
     A pair of raising cylinders  400  is provided for raising connected mast sections  200 ,  210  and  220  into the vertical position above substructure  300 , and also for raising substructure  300  from a transportable collapsed position to the illustrated deployed position. Raising cylinders  400  are also provided for lowering substructure  300  from the illustrated deployed position to a transportable collapsed position, and for lowering connected mast sections  200 ,  210  and  220  into the horizontal position above collapsed substructure  300 . 
     Raising cylinders  400  raise and lower connected mast sections  200 ,  210  and  220  by connection to wing brackets  250 . Raising cylinders  400  raise and lower substructure  300  by connection to cantilevers  500 . 
       FIG. 2  is an isometric exploded view of an embodiment of transport skid  600 . Transport skid  600  is loadable onto a standard low-boy trailer as is well known in the industry. Transport skid  600  has a forward end  602  and a rearward end  604 . Transport skid  600  supports a movable forward slider  620  and a rearward slider  630 . 
     Forward slider  620  is mounted on a carriage  610 . A forward hydraulic cylinder  622  is connected between carriage  610  and forward slider  620 . A pair of front slider pads  626  may be located between forward slider  620  and frame sides  606 . 
     Carriage  610  is located on skid  600  and movable in a direction between forward end  602  and rearward end  604 , separated by skid sides  606 . In one embodiment, a roller set  612  provides a rolling relationship between carriage  610  and skid  600 . 
     A motor  614  is mounted on carriage  610 . A pinion gear  616  is connected to motor  614 . A rack gear  618  is mounted lengthwise on skid  600 . Pinion gear  616  engages rack gear  618 , such that operation of motor  614  causes movement of carriage  610  lengthwise along skid  600 . 
     Rearward slider  630  is mounted on a rearward base  632 . A rearward hydraulic cylinder  634  is connected between rearward slider  630  and rearward base  632 . A pair of rear slider pads  636  may be located between rearward slider  630  and skid sides  606 . In one embodiment, bearing pads  638  are located on the upper surface of rearward slider  630  for supporting mast section  220 . 
     In one embodiment, an elevator  640  is located on each side of rearward slider  630 , between rearward slider  630  and skid  600 , each being movable between a raised and lowered position. 
       FIG. 3  is an isometric view of mast transport skid  600  of  FIG. 2 , illustrated assembled. Forward slider  620  is movable in the X-axis and Y-axis relative to skid  600 . Actuation of motor  614  causes movement of forward slider  620  along the X-axis. Actuation of forward cylinder  622  causes movement of forward slider  620  along the Y-axis. 
     Rearward slider  630  is movable independent of forward slider  620 . Rearward slider  630  is movable in the Y-axis and Z-axis relative to skid  600 . Actuation of rearward cylinder  634  causes movement of rearward slider  630  along the Y-axis. Actuation of elevators  640  causes movement of rearward slider  630  along the Z-axis. In one embodiment, elevators  640  are independently operable, thus adding to the degrees of freedom of control of rearward slider  630 . 
       FIGS. 4 through 7  illustrate the initial stages of the rig-up sequence performed in accordance with the present invention.  FIG. 4  is an isometric view of a first stage of the rig-up sequence for a drilling system, as performed in accordance with the present invention. Lower mast section  220  is carried on forward slider  620  and rearward slider  630  of transport skid  600 . Transport skid  600  is mounted on a trailer  702  connected to a tractor  700 . 
     A plurality of structural cross-members  222  (not shown) defines a mast framework width  224  (not shown) of lower mast section  220 . At this stage of the sequence, mast legs  230  are in the retracted position, and within framework width  224 . Also at this stage, wing brackets  250  are in the retracted position, and also within framework width  224 . By obtaining a stowed position of mast legs  230  and wing brackets  250 , the desired transportable framework width  224  of lower mast section  220  is achieved. Substructure  300  is in the collapsed position, on the ground, and being approached by tractor  700  and transport skid  600 . 
       FIG. 5  is an isometric view of a second stage of the rig-up sequence for a drilling system, as performed in accordance with the present invention. At this stage, tractor  700  and trailer  702  are backed up to a position of closer proximity to substructure  300 , which is on the ground in a collapsed position. Having moved mast legs  230  past the point of interference with raising cylinders  400 , legs  230  are deployed by mast leg cylinders  238  (not shown), which rotates legs about the axis Z of pivot connection  226 . 
     Each mast leg pair  230  has a front leg  232  and a rear leg  234 . Shoe connectors  236  are located at the base of legs  230 . Front shoes  332  and rear shoes  334  are located on drilling floor  330  for receiving shoe connectors  236  of front legs  232  and rear legs  234 , respectively. A pair of inclined ramps  336  is located on drilling floor  330 , inclining upwards towards front shoes  332 . 
     Elevators  640  are actuated to raise rearward slider  630  and thus mast legs  230  of lower mast  220  along the Z-axis ( FIG. 3 ) above obstacles related to substructure  300  as tractor  700  and trailer  702  are backed up to a position of closer proximity to substructure  300  (see  FIG. 4 ). In this position (referring also to  FIG. 2 ), forward cylinder  622  of forward slider  620  and rearward cylinder  634  of rearward slider  630  are actuated to finalize Y-axis ( FIG. 3 ) alignment of mast legs  230  of lower mast section  220  with inclined ramps  336  ( FIGS. 4 and 5 ). The option of like or opposing translation of forward slider  620  and rearward slider  630  along the Y-axis is especially beneficial for this purpose. Using this alignment capability, shoe connectors  236  of front legs  232  are aligned with inclined ramps  336 . 
       FIG. 6  is an isometric view of a third stage of the rig-up sequence for a drilling system, as performed in accordance with the present invention. In this stage, rearward slider  630  is lowered by elevators  640  (not visible), positioning shoe connectors  236  of front legs  232  onto inclined ramps  336 . This movement disengages rearward slider  630  from lower mast section  220 . 
     Carriage  610  is translated from forward end  602  towards rearward end  604 . In one embodiment, this movement is accomplished by actuating motor  614 . Motor  614  rotates pinion gear  616  which is engaged with rack gear  618 , forcing longitudinal movement of carriage  610  and forward slider  620  along the X-axis ( FIG. 3 ). As a result, lower mast section  220  is forced over substructure  300 , as shoe connectors  236  slide up inclined ramps  336 . 
       FIG. 7  is an isometric view of a fourth stage of the rig-up sequence for a drilling system, as performed in accordance with the present invention. As shoe connectors  236  reach the top of inclined ramps  336 , they align with, and are connected to, front leg shoes  332 . 
     In the embodiment described, wing brackets  250  ( FIG. 9 ) are pivotally connected to lower mast section  220  proximate to, and above, pivot connections  226  ( FIG. 7 ). Wing brackets  250  are movable between a transportable stowed position and the illustrated deployed position. 
     A wing cylinder  252  ( FIG. 9 ) may be connected between lower mast section  220  and each wing bracket  250  for facilitating movement between the stowed and deployed positions. Connection sockets  254  are provided on the ends of wing brackets  250  for connection to raising cylinder  400 . As shown in  FIGS. 7 and 9 , wing brackets  250  are moved into the deployed position by actuating wing cylinders  252  ( FIG. 9 ). 
     Raising cylinder  400  is pivotally connected to base box  310 . In a preferred embodiment, raising cylinder  400  has a lower end  402  pivotally connected to base box  310  at a location between the pivotal connections of substructure legs  340  to base box  310  (see  FIG. 18 ). Raising cylinder  400  has an opposite articulating end  404  (see  FIG. 9 ). In a preferred embodiment, raising cylinder  400  is a multi-stage telescoping cylinder capable of extension of a first stage  406 , a second stage  408  and a third stage  410 . A positioning cylinder  412  may be connected to each raising cylinder  400  for facilitating controlled rotational positioning of raising cylinder  400 . 
     In the stage of the rig-up sequence illustrated in  FIG. 7 , raising cylinders  400  are pivotally moved into alignment with deployed wing brackets  250  for connection to sockets  254 . Notably, raising cylinders  400  bypass the transported framework width  224  of lower mast section  220  in order to connect to wing brackets  250  on the far side of lower mast section  220 . It is thus required that mast raising cylinders  400  be separated by a distance slightly greater than framework width  224 . Lower mast section  220  is now supported by wing brackets  250 . This is accomplished by the present invention without the addition of separately transported and assembled mast sections. 
     As described above, an embodiment of the invention further includes a retractable push point for raising substructure  300  significantly above drill floor  330  and significantly forward of lower mast section  220 . 
     Lower mast section  220  is lifted slightly by extension of first stage  406  of raising cylinder  400 , disengaging lower mast section  220  from transport skid  600 , allowing tractor  700  and trailer  702  to depart. 
     As seen in  FIG. 7 , mast legs  230  are pivotally deployed about first pivot axis Z (at  226 ), and wing brackets  250  are pivotally deployed about second pivot axis  264  that is substantially perpendicular to first pivot axis Z (at  226 ). 
       FIG. 8  is an isometric view of wing bracket  250  in accordance with an embodiment of the present invention.  FIG. 9  is an isometric view of wing bracket  250  in the deployed position relative to lower mast section  220 . Referring to the embodiment of wing bracket  250  illustrated in  FIG. 8 , wing bracket  250  is comprised of a framework  260  designed to fit within a portal  228  in lower mast section  220  (see  FIG. 9 ). Frame  260  has a pair of sockets  262  for pivotal connection to lower mast section  220  within portal  228 . The pivotal connection defines an axis  264  about which wing bracket  250  is deployed and stowed. In one embodiment, axis  264  is substantially perpendicular to first pivot axis Z (at  226 ) about which legs  230  are deployed and stowed. 
     A lug box  256  extends from frame  260 . Socket  254  is located on lug box  256 . An arm  270  extends inward towards the interior of lower mast section  220 . A bracket socket  272  is located near the end of arm  270 . 
     Referring to  FIG. 9 , wing cylinder  252  extends between lower mast section  220  and arm  270  to deploy and stow wing bracket  250 . In the deployed position, a bracket locking pin  274  extending through portal  228  passes through bracket socket  272  ( FIG. 8 ) to lock wing bracket  250  in the deployed position. With wing bracket  250  locked in the deployed position, raising cylinder  400  is extended. Lug box  256  receives articulating end  404  of raising cylinder  400 . A raising cylinder locking pin  258  is hydraulically operable to pass through articulating end  404  and socket  254  to lock raising cylinder  400  to wing bracket  250 . 
       FIGS. 10, 11 and 12  are side views illustrating a fifth, sixth and seventh stage of the rig-up sequence for a drilling system, as performed in accordance with the present invention. Referring to  FIGS. 10 through 11 , it is seen that subsequent tractor  700  and trailer  702  carry central mast section  210  for connection to lower mast section  220 , and carry upper mast section  200  for connection to central mast section  210 . At this time, the weight of the collective mast sections is born by the raising cylinder  400  as transmitted through the wing brackets  250 . Raising cylinder  400  can be extended to align connected mast sections with each incoming mast section. For example, raising cylinder  400  can be extended to align connected mast sections  210  with  220 , and  200  with  210 . 
       FIGS. 13 and 14  are side views illustrating an eighth and ninth sequence for a drilling system, as performed in accordance with the present invention. In these steps, lower mast section  220  (and connected central and upper mast sections  210  and  200 ) is raised into a vertical position. In  FIG. 13 , lower mast section  220  is illustrated pivoted upwards by extension of first stage  406  and second stage  408  of raising cylinder  400 . In  FIG. 14 , lower mast section  220  is illustrated pivoted into the fully vertical position by extension of third stage  410  of raising cylinder  400 . 
       FIG. 15  is an isometric view of cantilever  500 , shown in accordance with the present invention. Cantilever  500  has a lower end  502  for pivotal connection to drill floor framework  320  of substructure  300 . Cantilever  500  has an upper end  504  for connection to articulating end  404  of raising cylinder  400 . A load pad  508  is provided for load bearing engagement with a beam brace  328  (not shown) located on substructure  300 . A backer panel  510  provides a complementary section of drill floor  330  when cantilever  500  is in the stowed position. 
     Cantilever  500  is movable between a transportable stowed position and a deployed position. In the stowed position, cantilever  500  is located beneath drill floor  330 . In the deployed position, upper end  504  of cantilever  500  is raised above drill floor  330  for connection to articulating end  404  of raising cylinder  400 . A cantilever cylinder  506  (not shown) may be provided for moving cantilever  500  between the transportable stowed position and the deployed position. 
       FIGS. 16, 17, 18, and 19  are side views illustrating tenth, eleventh, twelfth, and thirteenth stages of the rig-up sequence for a drilling system, illustrating the erection of substructure  300 , as performed in accordance with the present invention. In  FIG. 16 , raising cylinder  400  has been detached from wing brackets  250 , and articulating end  404  of raising cylinder  400  has been retracted. Wing brackets  250  may remain in the deployed position during drilling operations. 
     Cantilever  500  has been moved from the stowed position beneath drill floor  330  into the deployed position in which upper end  504  of cantilever  500  is above drill floor  330 . Cantilever  500  may be moved between the stowed and deployed positions by actuation of cantilever cylinder  506 . Upper end  504  of cantilever  500  is connected to articulating end  404  of raising cylinder  400 . In this position, load pad  508  of cantilever  500  is in complementary engagement with beam brace  328  for transmission of lifting force as applied by raising cylinder  400 . 
       FIG. 17  is a side view of an eleventh stage of the rig-up sequence for a drilling system, as performed in accordance with the present invention. In the view, first stage  406  of raising cylinder  400  is fully extended and second stage  408  ( FIG. 18 ) is being initiated. As a result of the force being applied on cantilever  500 , as transferred to beam brace  328 , drill floor framework  320  is raising off of base box  310  as substructure  300  is moved towards an erected position. 
       FIG. 18  is a side view of a twelfth stage of the rig-up sequence for a drilling system, as performed in accordance with the present invention. In this view, first stage  406  and second stage  408  of raising cylinder  400  have been extended to lift drill floor framework  320  over base box  310  as substructure  300  is moved into the fully deployed position with substructure legs  340  supporting the load of mast sections  200 ,  210 ,  220 , and drill floor framework  320 . Conventional locking pin mechanisms and diagonally oriented beams are used to prevent further rotation of substructure legs  340 , and thus maintain substructure  300  in the deployed position. 
       FIG. 19  is a side view of a thirteenth stage of the rig-up sequence for a drilling system, as performed in accordance with the present invention. In this view, articulating end  404  of raising cylinder  400  is disconnected from upper end  504  of cantilever  500 . Raising cylinder  400  is then retracted. Cantilever  500  is moved into the stowed position by actuation of cantilever cylinder  506 . In the stowed position, backer panel  510  of cantilever  500  becomes a part of drill floor  330 , providing an unobstructed space for crew members to perform drilling operations. 
       FIG. 20  is a diagram of the relationships between lower mast section  220  and substructure  300  raising components  250 ,  400  and  500  of the present invention. More specifically,  FIG. 20  illustrates one embodiment of preferred kinematic relationships between deployable wing bracket  250 , deployable cantilever  500  and raising cylinder  400 . 
     In one embodiment, upper end  504  of cantilever  500  is deployed to a location above drill floor  330  that is also forward of front leg shoes  332 . In one embodiment, pivotally connected end  402  of raising cylinder  400  is connected to substructure  300  at a location beneath and generally between front leg shoes  332  and rear leg shoes  334  of drill floor  330  of erected substructure  300 . Also in this embodiment, lower end  502  of cantilever  500  is pivotally connected at a location beneath drill floor  330  and forward of front leg shoes  332 . 
     As was seen in an embodiment illustrated in  FIG. 7 , mast legs  230  are pivotally deployed about a first pivot axis, and wing brackets  250  are pivotally deployed about a second pivot axis that is substantially perpendicular to the first pivot axis of mast legs  230 . Cantilever  500  is deployed about a third pivot axis that is substantially perpendicular to the first and second pivot axes of mast legs  230  and wing brackets  250 , respectively. 
     As seen in  FIG. 1 , there is a pair of raising cylinders  400 , each raising cylinder  400  connectable to a cantilever  500  and a wing  250 . In a preferred embodiment, the pair of raising cylinders  400  rotates in planes that are parallel to each other. In another preferred embodiment, cantilevers  500  rotate in planes that are substantially within the planes of rotation of the raising cylinders. This configuration has a number of advantages related to the alignment and connection of upper end  504  of cantilever  500  to articulating end  404  of raising cylinder  400 . This embodiment also optimizes accessibility of the deployed cantilevers  500  of sufficient size to carry the significant sub-lifting load beneath and above the very limited space on drill floor  330  and within drill floor framework  320 . This embodiment also provides deployed engagement of load pad  508  with a beam brace  328  located on substructure  300 , without placing a misaligned load of the pivotal connections of cantilevers  500  and cylinders  400 . It will be understood by one of ordinary skill in the art that a modest offset of the planes would behave as a substantial mechanical equivalent of these descriptions. 
     As was seen in an embodiment illustrated in  FIGS. 4-8 , mast legs  230  are pivotally deployed about a first pivot axis Z (at  226 ), and wing brackets  250  are pivotally deployed about a second pivot axis  264  that is substantially perpendicular to first pivot axis Z (at  226 ) of mast legs  230 . Cantilever  500  is deployed about a third pivot axis that is substantially perpendicular to the first and second pivot axes of mast legs  230  and wing brackets  250 , respectively. This embodiment is advantageous in that mast legs  230  may be pivoted about an axis that reduces the transport width of the mast. It is further advantageous in that the wings remain gravitationally retracted during transportation, and when deployed. 
     One such plane of rotation is illustrated in  FIG. 20 . As illustrated in  FIG. 20 , when connected to deployed wing brackets  250 , articulating end  404  forms a first arc A 1  upon extension of raising cylinder  400 . Arc A 1  is generated in a first arc direction as mast sections  200 ,  210  and  220  are raised. 
     When connected to deployed cantilever  500 , articulating end  404  forms a second arc A 2  upon extension of raising cylinder  400 . Arc A 2  is generated in a second arc direction opposite that of A 1 , as collapsed substructure  300  is raised. 
     A vertical line through the center of pivotally connected end  402  of cantilever  400  is illustrated by axis V. In a preferred embodiment, the intersection of first arc A 1  and second arc A 2  relative to axis V, is located within + or −10 degrees of axis V. 
     In one embodiment illustrated in  FIG. 20 , the angular disposition of raising cylinder  400  has four connected positions. The sequential list of the connected positions is: a) retracted connection to wing brackets  250 ; b) extended connection to wing brackets  250 ; c) retracted connection to cantilever  500 ; and d) extended connection to cantilever  500 . In the embodiment illustrated in  FIG. 20 , the angular disposition of raising cylinder  400  in position a is within 10 degrees of position d, and the angular disposition of raising cylinder  400  in position b is within 10 degrees of position c. The angular disposition of each position a, b, c, and d to vertical axis V is denoted as angles a′, b′, c′, and d′, respectively. 
     Having connected positional alignments within approximately 10 degrees optimizes the power and stroke of raising cylinder  400 . Also, having connected positional alignments b and c within approximately 10 degrees speeds alignment and rig-up of drilling system  100 . 
       FIG. 21  is a diagram of the relationship between raising cylinder  400 , deployable cantilever  500  and substructure leg  340 . In this diagram, substructure leg  340  is relocated for visibility of the angular relationship to raising cylinder  400 , as represented by angle w. Angle w is critical to the determination of the load capacity requirement of raising cylinder  400 . Without the benefit of the higher push point provided by deployable cantilever  500 , angle w would be approximately 21 degrees of lees for the embodiment shown. By temporarily raising the push point or pivotally connected end  402  above drill floor  330 , w is increased, lowering the load capacity requirement of raising cylinder  400 . 
     Provided in combination with deployable wing brackets  250 , the configuration of drilling rig assembly  100  of the present invention permits the optimal sizing of mast raising cylinders  400 , as balanced between retracted dimensions, maximum extension and load capacity, all within the fewest hydraulic stages. Specifically, mast raising cylinders  400  can achieve the required retracted and extended dimensions to attach to wing brackets  250  and extend sufficiently to fully raise mast sections  200 ,  210  and  220 , while also providing an advantageous angular relationship between substructure legs  340  and raising cylinder  400  such that sufficient lift capacity is provided to raise substructure  300 . This is all accomplished with the fewest cylinder stages possible, including first stage  406 , second stage  408  and third stage  410 . 
     As seen in the embodiment illustrated in  FIG. 21 , connection of upper end  504  of cantilever  500  to articulating end  404  of raising cylinder  400 , when substructure  300  is in the stowed position, forms an angle x between cantilever  500  and raising cylinder  400  of between 70 and 100 degrees. Extension of raising cylinder  400  to deploy substructure  300  reduces the angle between cantilever  500  and raising cylinder  400  to between 5 and 35 degrees. 
       FIG. 22  is a diagram of drilling rig assemblies  100  of three different sizes, each using the same raising cylinder pair  400  in combination with the same deployable cantilever  500  and deployable wing bracket  250 . 
     As seen in  FIG. 22 , the configuration of drilling rig assembly  100  of the present invention has the further benefit of enabling the use of one size of raising cylinder pair  400  in the same configuration with wing brackets  250  and cantilever  500  to raise multiple sizes of drilling rig assemblies  100 . As seen in  FIG. 22 , a substructure  300  for a 550,000 lb. hook load drilling rig  100  is shown having a lower ground to drill floor  330  height than does substructures  302  and  304 . Drilling rig designs for drilling deeper wells may encounter higher subterranean pressures, and thus require taller BOP stacks beneath drill floor  330 . As illustrated, the same wing brackets  250 , cantilever  500  and the raising cylinders  400  can be used with substructure  302  for a 750,000 lb. hook load drilling rig  100 , or with substructure  304  for a 1,000,000 lb. hook load drilling rig  100 . 
     As also illustrated in  FIG. 22 , the configuration of drilling rig assembly  100  of the present invention has a drill floor  330  height to ground of distance “h” which is less than 8 feet. This has the significant advantage of minimizing the incline and difficulty of moving mast sections  200 ,  210 ,  220  along inclined ramps  336  from the transport position into connection with front shoes  332  on top of collapse substructure  300 . This is made possible by the kinematic advantages achieved by the present invention. 
     As described, the relationships between the several lifting elements have been shown to be extremely advantageous in limiting the required size and number of stages for raising cylinder  400 , while enabling craneless rig-up of masts ( 200 ,  210 ,  220 ) and substructure  300 . As further described above, the relationships between the several lifting elements have been shown to enable optimum positioning of a single pair of raising cylinders  400  to have sufficient power to raise a substructure  300 , and sufficient extension and power at full extension to raise a mast ( 200 ,  210 ,  220 ) without the assistance of intermediate booster cylinder devices and reconnecting steps, and to permit such expedient mast and substructure raising for large drilling rigs. 
     Referring back to  FIGS. 4 through 7, 9, 13 through 14, and 16 through 19 , a method of assembling a drilling rig  100  is fully disclosed. The disclosure above, including the enumerated figures, provides for steps comprising: setting collapsible substructure  300  onto a drilling site; moving lower mast section  220  into proximity with substructure  300  ( FIGS. 4-6 ); pivotally attaching lower mast section  220  to a drill floor  330  of substructure  300  ( FIG. 7 ); pivotally deploying a pair of wing brackets  250  outward from a stowed position within lower mast section  220  to a deployed position external of lower mast section  220  ( FIGS. 7 and 9 ); connecting articulating ends  404  of a pair of raising cylinders  400  (having opposite pivotally connected end  402  connected to substructure  300 ) to each wing bracket  250  ( FIG. 7 ); extending raising cylinders  400  so as to rotate lower mast section  220  from a substantially horizontal position to an erect position above drill floor  330 ; pivotally deploying a pair of cantilevers  500  upward from a stowed position beneath drill floor  330  to a deployed position above drill floor  330 ; connecting articulating ends  404  of raising cylinders  400  to each deployed cantilever  500 ; and extending raising cylinders  400  so as to lift substructure  300  from a stowed, collapsed position to a deployed, erect position. 
     In another embodiment, shown in  FIGS. 10 through 12 , raising cylinders  400  are adjusted as central mast section  210  and upper mast section  200  are sequentially attached to lower mast section  220 . 
     As will be understood by one of ordinary skill in the art, the sequence of the steps disclosed may be modified and the same advantageous result obtained. For example, the wing brackets may be deployed before connecting the lower mast section to the drill floor (or drill floor framework). 
     Having thus described the present invention by reference to certain of its preferred embodiments, it is noted that the embodiments disclosed are illustrative rather than limiting in nature and that a wide range of variations, modifications, changes, and substitutions are contemplated in the foregoing disclosure and, in some instances, some features of the present invention may be employed without a corresponding use of the other features. Many such variations and modifications may be considered desirable by those skilled in the art based upon a review of the foregoing description of preferred embodiments. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.

Technology Classification (CPC): 4