Abstract:
A land rig including a mast, a substructure beneath the mast, the substructure having a top part, movement apparatus connected to the substructure, the movement apparatus connected to the mast, the movement apparatus for moving the mast and for moving the top part of the substructure. This abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims, 37 CFR 1.72(b).

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    This invention is directed to land rigs; such rigs for wellbore drilling; such rigs with an erectable mast and/or substructure portion; and methods of their use. 
         [0003]    2. Description of Related Art 
         [0004]    The prior art discloses a variety of rigs used in drilling and various wellbore operations; for example, and not by way of limitation, U.S. Pat. Nos. 3,340,938; 3,807,109; 3,922,825; 3,942,593; 4,269,395; 4,290,495; 4,368,602; 4,489,526; 4,569,168; 4,837,992; 6,634,436; 6,523,319 and the references cited in these patents—all these patents incorporated fully herein for all purposes. 
         [0005]    In many land drilling operations, land rigs are delivered to a site, assembled and then disassembled. It is important that land rig components be easily transported and assembled. Costs associated with land rigs and associated equipment, can be calculated on a per hour or per day basis, and, therefore, efficient takedown, transport, and setup operations are desirable. 
         [0006]    U.S. Pat. No. 3,922,825 discloses a rig with a stationary substructure base and a movable substructure base mounted thereon which is coupled to the stationary base and swings upright into an elevated position on a series of struts that are connected to the stationary base with swivel connections at each end. The movable base is otherwise stationary since neither the stationary base nor the movable base are mobile or repositionable without the use of an auxiliary crane or the like. 
         [0007]    The movable substructure base and the drill mast are raised with a winch mounted on an auxiliary winch truck. 
         [0008]    U.S. Pat. No. 3,942,593 discloses a mobile well drilling rig apparatus which has a trailerable telescoping mast and a separate sectionable substructure assembly with a rig base, a working floor, and a rail structure. The mast is conveyed to the top of the substructure by rollers and is raised by hydraulic raising apparatus to an upright position. With such a system the mast assembly can be relatively long when transporting it and the mast can be unstable during raising. This system uses drawlines and winch apparatus to raise the mast onto the working floor. 
         [0009]    U.S. Pat. No. 6,634,436 discloses a mobile land drilling apparatus and method. The rig has a mobile telescoping substructure box. A lifting apparatus selectively supports the mobile telescoping substructure box unit in a raised position and lowered position. An extension cylinder further extends the mobile telescoping substructure box unit in telescopic extension. A stationary frame member and a telescoping frame member have a plurality of cables attached thereto for supporting the telescoping frame member when extended. A trolley winch allows completion of the rig assembly without an external crane. 
       BRIEF SUMMARY OF THE INVENTION 
       [0010]    The present invention, in certain aspects, provides a land rig with an erectable mast and substructure, with part of the upper substructure and the mast raised by movement apparatus (e.g. winch apparatus, one, two, or more winches; hydraulic cylinder apparatus, electrical movement apparatus, powered screw jacks, or air/hydraulic apparatuses). 
         [0011]    In certain aspects, the present invention discloses a land rig in which a height-adjustable A-frame system is used in erecting the mast and raising part of the substructure. 
         [0012]    In certain aspects, the present invention provides a land rig for erecting a mast and raising a substructure in which main lines need not be unhooked and repositioned during raising operations. 
         [0013]    In certain aspects, the present invention discloses a land rig with a movable and repositionable sheave assembly which facilitates operations. 
         [0014]    In certain aspects, the present invention discloses a land rig in which lines used for mast erection and raising of part of a substructure need not be unpinned or moved during drilling operations. 
         [0015]    In certain aspects, the present invention discloses land rigs in which the apparatus for erecting a mast and raising part of a substructure are located apart from a drilling area of the rig once the mast is erected so that the apparatus does not interfere with rig operations. 
         [0016]    In certain particular aspects hydraulic winches (one, two, three, four, or more) such as model No. 750-123 from Lantec Company are used in embodiments of the present invention. 
         [0017]    In certain aspects, the present invention discloses a land rig with a mast; a substructure beneath the mast, the substructure having a top part; movement apparatus connected to the substructure, and connected to the mast; the movement apparatus for moving the mast and for moving the top part of the substructure. 
         [0018]    In certain aspects, the present invention discloses methods for erecting a land rig, the land rig having a mast, a substructure beneath the mast, the substructure having a top part, movement apparatus connected to the substructure and to the mast, the movement apparatus for moving the mast and for moving the top part of the substructure, the method including: erecting the mast with the movement apparatus; and raising the top part of the substructure with the movement apparatus. 
         [0019]    Accordingly, the present invention includes features and advantages which are believed to enable it to advance land rig technology. Characteristics and advantages of the present invention described above and additional features and benefits will be readily apparent to those skilled in the art upon consideration of the following detailed description of preferred embodiments and referring to the accompanying drawings. 
         [0020]    Certain embodiments of this invention are not limited to any particular individual feature disclosed here, but include combinations of them distinguished from the prior art in their structures, functions, and/or results achieved. Features of the invention have been broadly described so that the detailed descriptions that follow may be better understood, and in order that the contributions of this invention to the arts may be better appreciated. There are, of course, additional aspects of the invention described below and which may be included in the subject matter of the claims to this invention. Those skilled in the art who have the benefit of this invention, its teachings, and suggestions will appreciate that the conceptions of this disclosure may be used as a creative basis for designing other structures, methods and systems for carrying out and practicing the present invention. The claims of this invention are to be read to include any legally equivalent devices or methods which do not depart from the spirit and scope of the present invention. 
         [0021]    What follows are some of, but not all, the objects of this invention. In addition to the specific objects stated below for at least certain preferred embodiments of the invention, there are other objects and purposes which will be readily apparent to one of skill in this art who has the benefit of this invention&#39;s teachings and disclosures. It is, therefore, an object of at least certain preferred embodiments of the present invention to provide the embodiments and aspects listed above and: 
         [0022]    New, useful, unique, efficient, non-obvious land rigs, apparatus for raising parts of a land rig (mast and/or part of substructure), and methods of their use; and 
         [0023]    Such systems in which mast erecting apparatus and/or substructure portion raising apparatus is located away from a drilling end of a rig; 
         [0024]    Such a rig with one or more height-adjustable A-frames as pat of the mast erection apparatus. 
         [0025]    The present invention recognizes and addresses the problems and needs in this area and provides a solution to those problems and a satisfactory meeting of those needs in its various possible embodiments and equivalents thereof. To one of skill in this art who has the benefits of this invention&#39;s realizations, teachings, disclosures, and suggestions, various purposes and advantages will be appreciated from the following description of preferred embodiments, given for the purpose of disclosure, when taken in conjunction with the accompanying drawings. The detail in these descriptions is not intended to thwart this patent&#39;s object to claim this invention no matter how others may later attempt to disguise it by variations in form or additions of further improvements. 
         [0026]    The Abstract that is part hereof is to enable the U.S. Patent and Trademark Office and the public generally, and scientists, engineers, researchers, and practitioners in the art who are not familiar with patent terms or legal terms of phraseology to determine quickly from a cursory inspection or review the nature and general area of the disclosure of this invention. The Abstract is neither intended to define the invention, which is done by the claims, nor is it intended to be limiting of the scope of the invention or of the claims in any way. 
         [0027]    It will be understood that the various embodiments of the present invention may include one, some, or all of the disclosed, described, and/or enumerated improvements and/or technical advantages and/or elements in claims to this invention. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0028]    A more particular description of embodiments of the invention briefly summarized above may be had by references to the embodiments which are shown in the drawings which form a part of this specification. These drawings illustrate certain preferred embodiments and are not to be used to improperly limit the scope of the invention which may have other equally effective or equivalent embodiments. 
           [0029]      FIG. 1  is a front perspective schematic view of a land rig according to the present invention. 
           [0030]      FIG. 2  is a rear perspective schematic view of a land rig according to the present invention. 
           [0031]      FIG. 3  is a side view of the land rig of  FIG. 1 . 
           [0032]      FIG. 4A  is an enlargement of part of the land rig of  FIG. 1 . 
           [0033]      FIG. 4B  is a top view of part of the land rig of  FIG. 1 . 
           [0034]      FIG. 4C  is a perspective view of part of the land rig of  FIG. 1 . 
           [0035]      FIG. 4D  is a cross-section view along line  4 D- 4 D of  FIG. 4A . 
           [0036]      FIG. 5A  is a side view showing a step in a method for making part of the land rig of  FIG. 1 . 
           [0037]      FIG. 5B  is a side view showing a step in a method for making part of the land rig of  FIG. 1 . 
           [0038]      FIG. 5C  is a side view showing a step in a method for making part of the land rig of  FIG. 1 . 
           [0039]      FIG. 5D  is a side view showing a step in a method for making part of the land rig of  FIG. 1 . 
           [0040]      FIG. 5E  is a side view showing a step in a method for making part of the land rig of  FIG. 1 . 
           [0041]      FIG. 5F  is an enlargement of part of the system of  FIG. 5A . 
       
    
    
       [0042]    Presently preferred embodiments of the invention are shown in the above-identified figures and described in detail below. Various aspects and features of embodiments of the invention are described below and some are set out in the dependent claims. Any combination of aspects and/or features described below or shown in the dependent claims can be used except where such aspects and/or features are mutually exclusive. It should be understood that the appended drawings and description herein are of preferred embodiments and are not intended to limit the invention or the appended claims. On the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the invention as defined by the appended claims. In showing and describing the preferred embodiments, like or identical reference numerals are used to identify common or similar elements. The figures are not necessarily to scale and certain features and certain views of the figures may be shown exaggerated in scale or in schematic in the interest of clarity and conciseness. 
         [0043]    As used herein and throughout all the various portions (and headings) of this patent, the terms “invention”, “present invention” and variations thereof mean one or more embodiment, and are not intended to mean the claimed invention of any particular appended claim(s) or all of the appended claims. Accordingly, the subject or topic of each such reference is not automatically or necessarily part of, or required by, any particular claim(s) merely because of such reference. So long as they are not mutually exclusive or contradictory any aspect or feature or combination of aspects or features of any embodiment disclosed herein may be used in any other embodiment disclosed herein. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0044]      FIGS. 1 ,  2  and  3  show a land rig  10  according to the present invention which includes an A-frame apparatus  20  mounted on a substructure  40  and a mast system  60  (with a mast  11 ) movable from a generally horizontal position (as shown, e.g. in  FIGS. 3 and 5A ) to an erect, upright position (as shown, e.g. in  FIGS. 5D ,  5 E). 
         [0045]    The land rig  10  may include any and all the typical associated equipment, controls, hoists, drawworks, apparatuses, devices and systems used with any known land rig. As shown the land rig  10  includes tubular rotation apparatus (e.g. a top drive system  12  and/or a rotary apparatus  13 ) on the mast  11 ; a crown sheave or block  14 ; a travelling block  15  (see  FIG. 3 ); a raising sheave  16 ; an optional racking board  17 ; mast ends  18 , two of which,  18   a , pivot on a top part  43  of a substructure  40  and two of which,  18   b , are selectively connectible to the top part  43 ; and a drawworks system  19 . 
         [0046]    The mast  11  may be any suitable known mast (single-piece, multi-piece, and/or telescoping). As shown the mast  11  includes two parts  11   a  and  11   b  with part  11   b  movable up from part  11   a.    
         [0047]    The substructure  40  includes a base  41 ; movable support apparatus  42 ; and the top  43  (the rig floor) supported in certain positions by a movable support apparatus  42 . The movable support apparatus  42  includes a series of spaced-apart support beams or struts  44  each of whose ends are pivotably connected to the top  43  or the base  41  of the substructure  40 . There are two A-frame apparatuses  20 , one on each side of the rig as shown in  FIG. 2  with a total of four winches. It is within the scope of the present invention to use one or at least one winch; e.g. a single winch centered in the rig, e.g. useful in smaller, lighter and/or mobile rig systems. 
         [0048]    Each A-frame apparatus  20  includes two A-frame sections  20   a ,  20   b  each with two legs ( 21 ,  22 , A-frame  20   a ;  23 ,  24 , A-frame  20   b ) each with two parts ( 21   a ,  21   b  and  22   a ,  22   b ,  23   a ,  23   b  and  24   a ,  24   b ;  23   a ,  23   b ,  24   a ,  24   b  not shown. The parts telescope with respect to each other, one inside the other, to provide height adjustability for the A-frame apparatus  20 . 
         [0049]    Each A-frame  20  has a winch  25   a ; an idler sheave  26   a ; a frame sheave  27   a , a winch  25   b ; and idler sheave  26   b ; a frame sheave  27   b , raising apparatuses  28   a ,  28   b  which raise and lower the A-frame as the legs ( 21 ,  22 ;  23 ,  24 ) extend (raising) or retract (lowering). Any suitable raising apparatus may be used, e.g. hydraulic cylinders, air cylinders, piston/cylinder apparatuses, and electric screw jacks. As shown, the raising apparatuses  28   a ,  28   b  are telescoping hydraulic piston/cylinder apparatuses. 
         [0050]    Lines  29   a ,  29   b  from the winches  25   a ,  25   b , respectively, extend around the idler sheaves  26   a ,  26   b , to the frame sheaves  27   a ,  27   b  and to and around raising sheaves  16   a ,  16   b  (raising sheave  16   a  shown; raising sheave  16   b  not shown). 
         [0051]    The movable sheaves are movable in trolley guide tracks on the mast.  FIG. 4D  shows the movable sheave  16   a  with wheels  81  connected to a sheave body  82  The wheels  81  move in a trolley guide track  11 A of the mast  11 . Pins  84  releasably pin the sheave body  82  to parts  11   p  of the mast  11 . Similarly, pins through holes  86  in the body  82  releasably connect the body  82  to the top  43  of the substructure  40 . As shown the movable sheave  16   a  has recesses  16   r  for six lines. 
         [0052]      FIG. 5F  shows a typical kickover cylinder apparatus  90  which provides starting force to move the top  43  toward a lowered position. The apparatus  91  has a mounting structure  92  for mounting a movement apparatus  91  to the body  82 . Via a member  93  force from the movement apparatus  91  is transferred to the top  43  of the substructure  40 . The kickover cylinder apparatus  90  exerts force against the top  43  moving the top  43  forward, resulting in certain of the legs  44  (which are initially vertical) moving so that they are at an angle to the top  43 . 
         [0053]    As shown in  FIG. 5A , the raising apparatus  28   a  has raised the A-frame  20  (as shown). The legs  21 ,  22 ,  23 ,  24  have been extended with parts pinned or otherwise locked together. The A-frame apparatus is now in position to raise the mast  11 . 
         [0054]    As shown in  FIG. 5B  the winches  25   a ,  25   b  have raised the mast  11  (by taking in lines  29   a ,  29   b ), the mast has pivoted on the mast ends  18   a , and the mast ends  18   b  have been connected to the top  43  of the substructure  40  (e.g. with removable pins extending through the mast ends  18   b  into eyes on the top  43 . The legs  21 ,  22 ,  23 , and  24  have been locked in an extended position with pins through the leg parts. 
         [0055]    The racking board  17  has moved into the position shown in  FIG. 5B  and is held in place by lines  17   a ,  17   b  connected between the racking board  17  and the mast  11  (line  17   a ) and between the racking board  17  and a belly board  17   c . The racking board  17  can be movably attached to the mast  11  initially (e.g. before the step of  FIG. 5A ) or it can be connected to the mast  11  at any time. 
         [0056]    As illustrated in  FIG. 5C , the movable sheaves  16   a ,  16   b  have been moved down on channel-shaped guides  39  (see  FIG. 4A ) to the position shown in  FIG. 5C  and are then releasably connected to the top  43  of the substructure  40 . The sheaves  16   a ,  16   b  are moved up and down, e.g., by an auxiliary winch  70 . It is within the scope of the present invention to move the movable sheaves  16   a ,  16   b  using any suitable movement apparatus, including, but not limited to, hydraulic cylinder apparatus, pneumatic cylinder apparatus, and/or electric motor(s). 
         [0057]    As shown in  FIG. 5D , the raising apparatuses  28   a ,  28   b  have lowered the A-frames  20  (so the angle for the lines  29  is correct so that the winches  25   a ,  25   b  can raise the top  43  of the substructure  40  to the position of  FIG. 5E . The lower ends of the raising apparatuses pivotably connected to the top  43  of the substructure. Also the winches  25   a ,  25   b  are located relatively far away from the mast  11  and from operations associated with the rig. 
         [0058]    The winches  25   a ,  25   b  then take in lines  29  to raise the top  43  of the substructure  40  as shown in  FIG. 5E . In this position the lines  29  are positioned as shown in  FIG. 5E  relative to the items on the top  43 , i.e., out of the way of a variety of items on the top  43  so that movement on and operations on the top  43  are not impeded by the lines  29 , and so that operations of the rig, particularly around the mast, are not impeded. 
         [0059]    As shown in  FIG. 5E , for efficiency of movement and for efficient lifting forces when the movable sheaves  16   a ,  16   b  are moved down on the mast and then connected to the top  43  of the substructure  40 , the movable sheaves  16   a ,  16   b  are connected at a point on the top  43  of the substructure  40  which is closer to the center of the top  43  (center as viewed in  5 E) than to the end (left end as viewed in  FIG. 5E ) of the top  43 . Also as shown in  FIG. 5E , the A-frames remain in place during rig operations, with lines attached and extending between sheaves so that systems are in place to lower the top  43  and lower the mast  11  when desired. The movable sheave assemblies move down on the tracks until eyes in them are aligned with corresponding eyes of the mast through which pins are releasably inserted while the wheels remain connected to the movable sheave assemblies. 
         [0060]    As shown in the various drawings the winches are located away from a drilling end of the rig (e.g.  FIGS. 1 ,  3 ) so that the winches, lines, and associated apparatuses and parts are subjected to less corrosion and contamination as compared to a location closer to the drilling end of the rig. 
         [0061]    The present invention, therefore, provides in some, but not in necessarily all, embodiments a land rig for wellbore operations, the land rig including: a mast; a substructure beneath the mast, the substructure having a top part; movement apparatus connected to the substructure, and connected to the mast; the movement apparatus for moving the mast and for moving the top part of the substructure. Such a land rig may one or some, in any possible combination, of the following: the substructure including a top part and a base, the top part movably connected to the base, the mast pivotably connected to the top part of the substructure; the movement apparatus having at least one winch apparatus including winch lines; movable line apparatus connected to the mast and movable up and down on a portion of the mast, the movement apparatus including winch lines passing through the movable line apparatus; the movable line apparatus movable down toward the top part of the substructure and releasably connectible to the top part of the substructure; the substructure including a top part and a base, the top part connected to the base, the movable line apparatus positionable at a point on the mast to facilitate erection of the mast by the movement apparatus, and the movable line apparatus positionable adjacent the top part of the substructure, the movable line apparatus releasably connectible to the top part to facilitate raising of the top part with respect to the base; support structure connecting the top part to the base; wherein the support structure includes a plurality of spaced-apart support members each support member with a first end pivotably connected to the top part and a second end pivotably connected to the base; the at least one winch apparatus is at least one A-frame structure and at least one winch and winch lines, the at least one A-frame structure having an A-frame top with a top sheave apparatus for the winch lines, and an A-frame movement device for moving the A-frame top up and down so that the winch lines are alternately positionable for movement of the mast and for movement of the top part of the substructure; wherein the at least one A-frame structure is a plurality of spaced-apart A-frame structures; wherein the at least one A-frame structure has a plurality of lockable telescoping legs; wherein the at least one winch apparatus is a plurality of spaced-apart winch apparatuses each with associated winch lines; the substructure including a top part and a base, the top part having a top part center and movably connected to the base, and the movement apparatus including lines connectible near the center of the top part; the substructure including a top part and a base, the top part having a top part center and movably connected to the base, and wherein the movable line apparatus is movable to a position near the center of the top part to facilitate raising of the top part with respect to the base; wherein the substructure includes a drilling end and a second end spaced-apart from the drilling end, the movement apparatus closer to the second end than to the drilling end; and/or wherein the winch lines can remain connected to the movable line apparatus during drilling by the land rig. 
         [0062]    The present invention, therefore, provides in some, but not in necessarily all, embodiments a land rig for wellbore operations, the land rig including: a mast, a substructure beneath the mast, the substructure having a top part, the top part having a top part center; movement apparatus connected to the substructure, and to the mast; the movement apparatus for moving the mast and for moving the top part of the substructure; the mast pivotably connected to the top part of the substructure; the substructure including a base, the top part movably connected to the base; the movement apparatus is at least one winch apparatus including winch lines; movable line apparatus connected to the mast and movable up and down on a portion of the mast; the movement apparatus including winch lines passing through the movable line apparatus; the movable line apparatus movable down toward the top part of the substructure and releasably connectible to the top part of the substructure; the movable line apparatus positionable at a point on the mast to facilitate erection of the mast by the movement apparatus; the line apparatus positionable adjacent the top part of the substructure; the movable line apparatus releasably connectible to the top part to facilitate raising of the top part with respect to the base; support structure connecting the top part to the base; wherein the support structure includes a plurality of spaced-apart support members each support member with a first end pivotably connected to the top part and a second end pivotably connected to the base; the at least one winch apparatus comprising at least one A-frame structure and at least one winch and winch lines; the at least one A-frame structure having an A-frame top with a top sheave apparatus for the winch lines; an A-frame movement device for moving the A-frame top up and down so that the winch lines are positionable for movement of the mast and for movement of the top part of the substructure; wherein the at least one winch apparatus is a plurality of spaced-apart winch apparatuses each with associated winch lines; wherein the substructure includes a drilling end and a second end spaced-apart from the drilling end; the movement apparatus closer to the second end than to the drilling end; and wherein the winch lines can remain connected to the movable line apparatus during drilling by the land rig. 
         [0063]    The present invention, therefore, provides in some, but not in necessarily all, embodiments methods for land rig operations including erecting a land rig, the land rig as any according to the present invention, the methods including: erecting a mast with a movement apparatus, and raising part of a rig substructure with the movement apparatus. Such methods may include one or some, in any possible combination, of the following: wherein the mast is pivotably connected to a top part of the substructure, the substructure includes a top part and a base, the top part movably connected to the base, movable line apparatus connected to the mast and movable up and down on a portion of the mast, the movement apparatus including winch lines passing through the movable line apparatus, the movable line apparatus movable down toward the top part of the substructure and releasably connectible to the top part of the substructure, the movable line apparatus positionable at a point on the mast to facilitate erection of the mast by the movement apparatus, the line apparatus positionable adjacent the top part of the substructure, the movable line apparatus releasably connectible to the top part to facilitate raising of the top part with respect to the base, the movement apparatus including at least one winch apparatus including winch lines, and the method further including erecting the mast using the at least one winch apparatus with winch lines passing through the movable line apparatus, moving the movable line apparatus adjacent the top part of the substructure and releasably connecting the movable line apparatus to the top part of the substructure, and raising the top part of the substructure with respect to the base; wherein the top part has a top part center and the movable line apparatus is connected to the top part near the top part center; wherein the substructure includes a drilling end and a second end spaced-apart from the drilling end, the movement apparatus closer to the second end than to the drilling end, and wherein the winch lines can remain connected to movable line apparatus during drilling by the land rig, the top part having a top part center, the method including drilling with the land rig while the winch lines are connected to the movable line apparatus, the movable line apparatus connected to the top part near the top part center during drilling. 
         [0064]    In conclusion, therefore, it is seen that the present invention and the embodiments disclosed herein and those covered by the appended claims are well adapted to carry out the objectives and obtain the ends set forth. Certain changes can be made in the subject matter without departing from the spirit and the scope of this invention. It is realized that changes are possible within the scope of this invention and it is further intended that each element or step recited in any of the following claims is to be understood as referring to the step literally and/or to all equivalent elements or steps. The following claims are intended to cover the invention as broadly as legally possible in whatever form it may be utilized. The invention claimed herein is new and novel in accordance with 35 U.S.C. § 102 and satisfies the conditions for patentability in § 102. The invention claimed herein is not obvious in accordance with 35 U.S.C. § 103 and satisfies the conditions for patentability in § 103. This specification and the claims that follow are in accordance with all of the requirements of 35 U.S.C. § 112. The inventors may rely on the Doctrine of Equivalents to determine and assess the scope of their invention and of the claims that follow as they may pertain to apparatus not materially departing from, but outside of, the literal scope of the invention as set forth in the following claims. All patents and applications identified herein are incorporated fully herein for all purposes. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures. It is the express intention of the applicant not to invoke 35 U.S.C. § 112, paragraph 6 for any limitations of any of the claims herein, except for those in which the claim expressly uses the words ‘means for’ together with an associated function.