Patent Grant
8814487
1. Field of the Disclosure
The present invention relates generally to methods and apparatus for handling pipes and other tubular members during drilling and/or workover operations of a well. More specifically, the present invention relates to an impact absorbing “diving board,” or access platform, of a “fingerboard,” or pipe racking assembly, used for staging pipes and other tubular members adjacent to a drilling rig in a substantially vertical orientation while the drilling and/or workover operations are being performed.
2. Description of the Related Art
Drilling masts are vertical structures that are commonly used to support a drill string while a well is being drilled. Drilling masts usually have a relatively compact, rectangular footprint, as opposed to a derrick structure, which typically has a steep pyramidal shape. The rectangular shape of the typical drilling mast also offers relatively good overall stiffness, which allows the mast to be lowered to a horizontal position. The compact, rectangular shape of the drilling mast structure therefore facilitates transportation of the drilling rig over surface roads, many times without the need for obtaining special shipping permits, and thereby making drilling masts very common on portable land-based drilling rigs.
During typical drilling operations, a string of drill pipe—shown as reference number 6 in
Due to the relatively compact footprint that may be associated with drilling mast structures, there may be very limited space available for storing the drill pipe and other tubular members adjacent to the drilling mast 2. Therefore, in many cases, the drill pipe may be vertically staged in a specially designed structural assembly—sometimes referred to as a racking board or fingerboard 5—that is attached to the drilling mast 2, as shown in
“Tripping” is a term of art used in drilling operations that generally refers to acts of either adding multiple joints of drill pipe to, or removing multiple joints of drill pipe from, a drilled wellbore. Oftentimes during the drilling operations, tripping operations may be performed wherein the drill string 6 is pulled from the wellbore in order to change the drill bit, or to run various other types of equipment, such as testing equipment and the like, into the wellbore on the end of the drill string 6. When tripping drill pipe out of the wellbore, the traveling block 3 and top drive assembly 4 may be raised until a stand of drill pipe (i.e., generally multiple connected sections, or joints, of drill pipe) extends above the drilling rig floor. In most cases, a stand of drill pipe may comprise two or three joints of drill pipe, with the most common pipe stand configuration being three joints of drill pipe, totaling approximately 90 feet in length. Thereafter, slips are placed between the string of drill pipe and the drilling rig floor in order to suspend the drill string 6 in and above the wellbore from a point beneath the bottom threaded joint of the stand of drill pipe that is to be removed from the drill string. In this position, the drill string 6 extends above the drilling rig floor 7, and the upper end, or box end, of the string is positioned above the plane of the fingerboard 5, which, as noted previously, may be located 75 feet or more above the drilling rig floor 7.
Once the drill string 6 has been suspended with its box end positioned above the fingerboard 5, the threaded connection between the stand of drill pipe and the remainder of the drill string 6 is then unthreaded, and the lower end, or pin end, of the stand is guided away from the remainder of the drill string 6 and wellbore and placed on a support pad—sometimes referred to as a setback—on the drilling rig floor 7. Next, the box end of the stand of drill pipe is removed from the traveling block 3/top drive assembly 4 and the stand is typically manually guided by drilling rig personnel to the fingerboard 5, where it is staged between a set of racking fingers 8 (see
The movement of stands of drill pipe from the top drive assembly 4 to the racking fingers 8 of the fingerboard 5 is often manually effectuated by rig personnel, who may pull and/or push the drill pipe to its proper staging location. Furthermore, it is generally well understood that such movements of large sections of drill pipe may involve a variety of difficulties that, if not properly addressed by rig personnel involved in the work, may be hazardous to those personnel working above the rig floor and near the fingerboard. For example, the job of maneuvering the stand of drill pipe to its proper staging location may entail such activities as reaching out from the area of the fingerboard 5 to where the stand of drill pipe is located above the centerline 9 (see
Recently, various efforts have been undertaken to automate at least some aspects of the operations that are commonly used for running drill pipe into and out of the wellbore—i.e., tripping the drill string—so as to avoid at least some of the constant interaction of rig personnel with the various pieces of equipment and materials that are in motion during drilling operations, such as the drill string 6, the traveling block 3, and/or the top drive assembly 4. For example, some complex automatic systems have been developed to perform the pipe handling steps of moving the stands of drill pipe between the pipehandler assembly 4a (see
During the above described pipe tripping operations, it is very common for the traveling block 3 to be raised and/or lowered very quickly, which can help to speed up these otherwise time-consuming—and costly—drill pipe handling operations. However, due to the speed of these activities, the time that rig personnel may have to react to anomalies in the overall operations—such as errors, mistakes, or oversights by other personnel, or to otherwise unanticipated equipment failures—may be significantly reduced, thereby increasing the likelihood that accidents may occur. By way of example, in some cases, the top drive assembly 4 may not be properly oriented or aligned during some phases of the operations, which may cause some portions of the top drive assembly 4 to project farther from the centerline 9 of the well than would otherwise be anticipated. In other cases, the links of the pipehandler assembly 4a may not be properly oriented or fully retracted, a situation which may also cause the top drive assembly 4 to project farther from the well centerline 9 than normal. Under such circumstances, it may be possible for the top drive assembly 4 to strike the diving board 11 as the top drive assembly 4 is being raised and/or lowered by the traveling block 3. The likelihood of such a strike may be further exacerbated in those cases where the diving board 11 includes a hinged extension section 11a, and when that hinged extension section 11a may be folded out for closer access.
The force that may be imparted to the diving board 11 by the moving mass of the traveling block 3, the top drive assembly 4, and the drill string 6—which will depend on the speed at which those elements are moving—may result in considerable damage to the structure of the diving board 11, the fingerboard 5, and even the top drive assembly 4. Furthermore, if proper safety procedures are not observed during drilling activities, there may be a substantial risk of injury to rig personnel during such occurrences. It should be further noted that any type of damage to the diving board 11, the fingerboard 5, and/or the top drive assembly 4 may result in significant and costly down-time for the rig while the necessary repairs are affected. Moreover, when the fingerboard 5 and diving board 11 incorporate devices and equipment associated with the types of complex automatic pipe handling systems discussed previously, the cost and down-time for repairing any damage may be substantially greater than that associated with relatively simple structural repairs.
Accordingly, there is a need to develop and implement new designs for the diving board structures of drilling rig fingerboards to address the issue of damage that may occur when the diving board may be inadvertently struck by drilling equipment during drilling operations. The present disclosure relates to methods and devices that may avoid, or at least reduce, the effects of one or more of the problems identified above.
The following presents a simplified summary of the present disclosure in order to provide a basic understanding of some aspects disclosed herein. This summary is not an exhaustive overview of the disclosure, nor is it intended to identify key or critical elements of the subject matter disclosed here. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is discussed later.
Generally, the subject matter disclosed herein relates to an impact absorbing “diving board,” or access platform, of a drilling rig fingerboard or pipe racking assembly. One illustrative diving board assembly of a drilling rig fingerboard assembly disclosed herein includes, among other things, a first end proximate the drilling rig and a second end positioned remote from the first end, where the first end is more proximal to the drilling rig than the second end. The illustrative diving board assembly further includes a clamping assembly operatively coupled to the first end and to the second end, where the clamping assembly is positioned between the first and second ends and defines a pinned connection adapted to permit a rotation of the first and second ends relative to a plane defined by the fingerboard assembly.
The present subject matter also discloses a pipe racking system of a drilling that includes, among other things, a fingerboard assembly adapted for staging one or more sections of pipe in a substantially vertical orientation, where at least a portion of the fingerboard assembly is positioned in a substantially horizontal plane and comprises two laterally opposing rows of racking fingers. The disclosed pipe racking system further includes a pivotable diving board assembly substantially disposed between the two laterally opposing rows of racking fingers, where the diving board assembly is adapted to provide access from the fingerboard assembly to one or more pipes used during normal drilling operations. Additionally, the pipe racking system disclosed herein also includes a diving board clamping assembly that is adapted to maintain the pivotable diving board assembly in a first position under a first operating condition and to permit an angular rotation of the pivotable diving board assembly to a second position located at an angle relative to the plane of the fingerboard assembly under a second operating condition.
In another illustrative embodiment of the present subject matter, a diving board assembly adapted to provide access to a fingerboard assembly of a drilling rig pipe racking system is disclosed herein. The disclosed diving board assembly includes, among other things, a first end proximate the drilling rig and a second end positioned remote from the first end, where the first end is more proximal to the drilling rig than the second end, and where the first and second ends are positioned in a first plane. The diving board assembly also includes at least one structural support member adapted to support a platform for accessing the fingerboard assembly, where the at least one structural support member is substantially parallel to the first plane. Furthermore, the diving board assembly includes a clamping assembly adapted to maintain the first plane of the diving board assembly substantially parallel to a plane defined by the fingerboard assembly during a normal operation of the drilling rig, where the plane of the fingerboard assembly is substantially horizontal.
The present subject matter also discloses a method of operation a rotatable impact-absorbing diving board assembly that includes installing a rotatable impact-absorbing diving board assembly proximate a fingerboard assembly of a drilling rig, where a plane of at least a portion of the fingerboard assembly is substantially horizontal. The method further includes, among other things, aligning the rotatable impact-absorbing diving board assembly with a plane that is substantially parallel to the plane of at least the portion of the fingerboard assembly, and clamping a clamping assembly of the rotatable impact-absorbing diving board assembly around a cylindrically shaped structural member, where the clamping assembly is adapted to permit an angular rotation of the rotatable impact-absorbing diving board assembly about a longitudinal axis of the cylindrically shaped structural member. Furthermore, the method includes causing an angular rotation of the rotatable impact-absorbing diving board assembly about the cylindrically shaped structural member.
The disclosure may be understood by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify like elements, and in which:
a is an elevation view of an illustrative prior art portable land-based drilling rig assembly;
b is a close-up elevation view of a fingerboard attached to a drilling mast of the illustrative prior art drilling rig assembly of
c is a plan view of the fingerboard and drilling mast of the illustrative prior art drilling rig assembly shown in
a is an isometric view of a fingerboard and an illustrative embodiment of the impact absorbing diving board of the present disclosure;
b is a plan view of the fingerboard and illustrative impact absorbing diving board shown in
c is a side elevation view of the fingerboard and illustrative impact absorbing diving board shown in
d is a front elevation view of the fingerboard and illustrative impact absorbing diving board shown in
e is a plan view of an illustrative impact absorbing diving board clamping assembly of the present disclosure;
f is an isometric view of the illustrative impact absorbing diving board clamping assembly shown in
g is a close-up isometric view of the illustrative impact absorbing diving board clamping assembly shown in
h is a close-up side elevation view of the illustrative impact absorbing diving board clamping assembly shown in
i is an isometric view of the fingerboard and illustrative impact absorbing diving board shown in
j is a side elevation view of the fingerboard and illustrative impact absorbing diving board shown in
k is an isometric view of the illustrative impact absorbing diving board shown in
While the subject matter disclosed herein is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular forms disclosed, but 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.
Various illustrative embodiments of the present subject matter are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.
The present subject matter will now be described with reference to the attached figures. Various systems, structures and devices are schematically depicted in the drawings for purposes of explanation only and so as to not obscure the present disclosure with details that are well known to those skilled in the art. Nevertheless, the attached drawings are included to describe and explain illustrative examples of the present disclosure. The words and phrases used herein should be understood and interpreted to have a meaning consistent with the understanding of those words and phrases by those skilled in the relevant art. No special definition of a term or phrase, i.e., a definition that is different from the ordinary and customary meaning as understood by those skilled in the art, is intended to be implied by consistent usage of the term or phrase herein. To the extent that a term or phrase is intended to have a special meaning, i.e., a meaning other than that understood by skilled artisans, such a special definition will be expressly set forth in the specification in a definitional manner that directly and unequivocally provides the special definition for the term or phrase.
Generally, the subject matter disclosed herein relates to a pivotable, or rotatable, “diving board,” or access platform, of a drilling rig “fingerboard,” or pipe racking assembly, that is capable of absorbing high impact loads, such as blows from moving drilling equipment, while sustaining little or no significant damage.
In certain illustrative embodiments, the fingerboard assembly 105 may also include access platforms 110, which, as shown in
In some embodiments disclosed herein, the rotatable diving board 111 may be substantially centrally located between the two laterally opposing rows 108a, 108b (see
b is a plan view of the fingerboard assembly 105 and the illustrative impact absorbing diving board 111. In the embodiment shown in
As shown in
In some illustrative embodiments, the diving board 111 may also comprise a removable cover plate 111b located between the diving board extension section 111e and the diving board section 111r that is centrally positioned between the laterally opposing rows 108a, 108b of the racking fingers 108. In certain embodiments of the present disclosure, the removable cover plate 111b may comprise an appropriate deck plate 130, which may be removed to provide access to an impact absorbing diving board clamping assembly 150 (see
c is a side elevation view of the fingerboard assembly 105 and the illustrative impact absorbing diving board 111 depicted in
d is a front elevation view of the fingerboard assembly 105 and the illustrative impact absorbing diving board 111 depicted in
As discussed above, the diving board 111 may inadvertently be struck near the first end 111f by a traveling block and/or top drive assembly (not shown) during the drill string tripping operations. Depending on the conditions of the strike, such as the speed at which the traveling block is moving and the mass of the equipment or material being moved, the impact load imparted to the diving board 111 may sometimes be quite large, which could result in significant damage to the diving board 111, the fingerboard assembly 105, and/or other ancillary equipment, such as the STV 113. In order to avoid, or at least minimize, the type of damage that may occur as a result of an inadvertent diving board strike, the design of the diving board 111 may, in some illustrative embodiments, incorporate an impact absorbing diving board clamping assembly 150 (see
e is a plan view of one illustrative embodiment of an impact absorbing diving board clamping assembly 150 according to the present disclosure. In some embodiments, the clamping assembly 150 may comprise an upper clamp section 150a, a lower clamp section 150b (see
In some illustrative embodiments disclosed herein, the fasteners 154 may be suitably sized threaded fasteners, such as, for example, hex head bolts, machine screws, threaded studs, and the like. Furthermore, the size and material grade of fasteners 154 may be selected as necessary for the required fastener pre-load as discussed below, as well as the anticipated loading conditions during operation. For example, in certain embodiments, the threaded fasteners 154 may be 1½-8UN heavy hex head shoulder bolts, and may comprise a high strength material grade, such as A325, A490, Gr.8, and the like, although other sizes and material types may also be used. In particular embodiments, each of the fasteners 154 may pass through a corresponding hole in the upper clamp section 150a so as to engage a blind hole at a corresponding location in the lower clamp section 150b. In those embodiments wherein the fasteners 154 comprise threaded fasteners, the blind hole at each corresponding location in the lower clamp section 150b may be tapped and internally threaded with a thread type and size to match that of the threaded fasteners 154.
In some illustrative embodiments, a plurality of tension indicating washers 155 may be used in conjunction with each fastener 154 so as to ensure that a specific pre-load is maintained on each fastener during the normal operation of the diving board 111 and the impact absorbing diving board clamping assembly 150. For those embodiments of the present disclosure wherein the fasteners 154 may be heavy hex head shoulder bolts, the shoulder bolt fasteners 154 may be sized to impart a predetermined amount of compression to the plurality of tension indicating washers 155, thereby achieving the desired fastener pre-load without requiring a specific bolt torque setting. In other illustrative embodiments, the upper and lower clamp sections 150a, 150b may be coupled together using traditional a “through-bolting” technique, where the fasteners 154 may be threadingly coupled to a corresponding appropriately threaded nut (not shown). However, when utilizing the above-described “through-bolting” technique, control of the bolt torque used to make up the clamping assembly 150 during initial assembly may be required so as to achieve the desired pre-load. As shown in
In particular embodiments, a plurality of fasteners (not shown) may be used to facilitate the installation and removal of the removable cover plate 111b (see
In certain illustrative embodiments of the present disclosure, the upper and lower clamp sections 150a, 150b are adapted to engage with and clamp around a cylindrically shaped structural member 151 passing therebetween. Depending on the overall design requirements and anticipated loading criteria, the cylindrically shaped structural member 151 may be a hollow structural element, such as, for example, a section of pipe or mechanical tubing. In some embodiments, the cylindrically shaped structural member 151 may be, for example, a 10″ O.D. by ½″ wall thickness mechanical tubing, and may comprise carbon steel or low alloy steel material. For example, and depending on the anticipated loading and strength requirements, in certain illustrative embodiments the cylindrically shaped structural member 151 may comprise a hot-finished drawn-over-mandrel (HF DOM) mechanical tubing using carbon steel materials manufactured to ASTM 1010, 1015, 1018, 1020, 1026, and/or 1035 standards, and the like. Other tubing sizes and material grades may also be used. Furthermore, the cylindrically shaped structural member 151 may extend substantially across the width of the fingerboard assembly 105, and may be fixedly attached in any suitable fashion, such as by welding and the like, to the structural members 121 adjacent to and outboard of the two laterally opposing rows 108a, 108b (see
In certain embodiments, shear plates 152 may be fixedly attached, such as by welding and the like, to the cylindrically shaped structural member 151 immediately adjacent to and outboard of the side plates 153. Furthermore, as shown in
f is an isometric view of the illustrative impact absorbing diving board clamping assembly 150 shown in
As shown in
As shown in
h is a side elevation view of the illustrative impact absorbing diving board clamping assembly 150 shown in
As noted previously, in some illustrative embodiments, the fasteners 154 may be threaded fasteners, such as heavy hex head bolts and the like, which may pass through corresponding holes 154a in the upper clamp section 150a so as to engage internally threaded blind holes 154b at a corresponding location in the lower clamp section 150b. In particular embodiments of the present disclosure, the length 154L of the threaded fasteners 154—such as shoulder bolts, and the like—may be adjusted such that each of the threaded fastener 154 bottoms out when threaded into the respective threaded blind holes 154b, thereby leaving a space or gap 150g as shown in
i-2k show the fingerboard assembly 105 and an illustrative embodiment of the impact absorbing diving board 111 of the present disclosure after the diving board 111 may have been inadvertently struck near the first end 111f by a traveling block and/or top drive assembly during drilling rig operations. More specifically,
As noted previously, during the initial assembly of the impact absorbing diving board clamping assembly 150, the shear pins 156 (see
Accordingly, the shear strength of the shear pins 156, in combination with the static friction force generated by the clamping force between the upper and lower clamp sections 150a, 150b and the cylindrically shaped structural member 151, should be of sufficient magnitude to resist the moment loads on the clamping assembly 150 that may be anticipated during normal rig operations. In some illustrative embodiments, the normal operating moment loads on the clamping assembly 150 may include, for example, dead load moments caused by the dead weight of the diving board 111 (including the structural support members 122), the dead weight of the STV control pod 112 (including the control panel 114 and STV storage bay 113b), the dead weight of the STV 113, and the dead weight of any ancillary equipment associated with the operation of the STV 113—such as tracks, drive motors, controls and the like—that may be mounted on or attached to the diving board 111 and/or the structural support member 122. The normal operating moment loads on the clamping assembly 150 may also include, for example, live load moments caused by personnel, equipment, and/or materials present on the impact absorbing diving board 111 during rig operations, as well as, for example, dynamic load moments caused by movement of the STV 113 during pipe handling operations.
On the other hand, in order for the impact absorbing diving board 111 to be able to pivot or rotate about the clamping assembly 150 after being impacted from above or below by a traveling block and/or top drive assembly of a drilling rig, the combined shear strength of the shear pins 156 and static friction force imparted by the clamping assembly 150 on the cylindrically shaped structural member 151 must be overcome by the additional dynamic moment that is created when the diving board 111 is struck near the first end 111f. Furthermore, in order to protect the diving board 111, the automatic pipe handling system, and/or the fingerboard assembly 105 from incurring undue damage during such an event, the magnitude of the combined shear strength and static friction force discussed above should be low enough so that the shear pins 156 are sheared and the friction force on the cylindrically shaped structural member 151 is overcome when the diving board 111 is struck.
Accordingly, in particular embodiments disclosed herein, the size, material, and mechanical properties of the shear pins 156, and the amount of pre-load imparted to the fasteners 154 during initial assembly of the clamping assembly 150 (and the commensurate clamping force on the cylindrically shaped structural member 151), may each be adjusted so as to hold the clamping assembly 150 and the diving board 111 in a substantially horizontal orientation under normal rig operations and loading conditions, while also permitting the diving board 111 to rotate or pivot about the clamping assembly 150 in certain instances when the diving board 111 may be inadvertently impacted by a traveling block and/or top drive assembly during pipe handling operations. In yet other embodiments, the shear strength of the shear pins 156 and the static friction force on the cylindrically shaped structural member 151 may be further adjusted so that the diving board 111 is permitted to rotate or pivot about the clamping assembly 150 only in those circumstances when the magnitude of any impact load on the diving board 111 exceeds a value that is known to cause an unacceptably high level of damage to a diving board assembly (or to its associated pipe handling accessories and components) that does not otherwise comprise a clamping assembly, such as a clamping assembly 150 of the present disclosure.
It should be noted that, after the occurrence of an impact load event that may cause the impact absorbing diving board 111 to rotate or pivot about the clamping assembly 150 as described above—i.e., wherein the shear pins 156 are sheared and the friction force on the cylindrically shaped structural member 151 is overcome—the friction force should still be of such a magnitude as to be able to hold the diving board in its rotated position. That is, the friction force between the clamp assembly 150 and the cylindrically shaped structural member 151 should be sufficiently high enough to eventually overcome any residual angular momentum imparted to the diving board 111 by a traveling block and/or top drive assembly after the shear pins 156 have been sheared, so as to stop the rotational movement of the diving board 111. Once the rotational movement of the diving board 111 has been stopped, the friction force should be also be sufficiently high enough to resist at least the dead load moments described above, as well as any live load moments that may also be present. In this manner, the clamping assembly 150 acts as a “brake,” thereby preventing the impact absorbing diving board 111 from swinging freely up and/or down, which, if permitted, may under some circumstances cause additional impact loading on, and subsequent damage to, the diving board 111, the clamping assembly 150, and/or the fingerboard assembly 105, including the racking fingers 108. It should be further noted that the “braking” effect caused by the frictional force of the clamping assembly 150 may be of added importance in those embodiments wherein the diving board 111 comprises an automatic and/or remotely controlled pipe handling system, due to the significant amount of additional dead weight of (and the subsequent additional moment loads caused by) the materials and equipment of such a system, such as, for example, the diving board extension section 111e, the STV 113, the STV control pod 112, the control panel 114, and the like.
Depending on the magnitude of the impact load imparted to the impact absorbing diving board 111 when struck near the first end 111f by a traveling block and/or top drive assembly, the diving board 111 may rotate about the clamping assembly 150 at an angle 105a (see
In the event of an impact load occurrence that is of sufficient magnitude to cause the impact absorbing diving board 111 to rotate, the diving board 111 may be returned to its normal—i.e., substantially horizontal—operating position, and the clamping assembly 150 may be re-set in accordance with the following procedure. First, measures must be taken to support the dead weight of the diving board 111, including the dead weight of any additional or ancillary equipment and materials mounted on or attached to the diving board 111, such as the STV 113, the STV control pod 112, and the like. For example, the wire rope of an air hoist, or tugger, may be sheaved through the crown of the drilling rig and attached to one end of the diving board 111 so as to be able to support the dead load once the “braking” effect of the clamping assembly 150 has been eliminated. Depending on the dead weight distribution along the length of the diving board 111, and the specific location of the clamping assembly 150 relative to each end of the diving board 111, the dead load may be supported at the first end 111f of the diving board 111 proximate the drilling rig mast, or it may be supported at the second end 111s of the diving board 111 opposite the drilling rig mast.
Next, the pre-load on each of the plurality of fasteners 154 may be reduced so that the static friction force on the cylindrically shaped structural member 151 may be reduced, and the “braking” effect of the clamping assembly 150 may be effectively eliminated. For example, if the fasteners 154 are threaded fasteners, the threaded fasteners 154 may be sufficiently loosened to reduce the clamping force imparted on the cylindrically shaped structural member 151 by the upper and lower clamp sections 150a, 150b to a point where the dead load moments on the clamping assembly 150 are greater than the static friction force on the cylindrically shaped structural member 151.
Once the “braking” effect of the clamping assembly 150 has been eliminated, and the dead weight of the diving board 111 (and that of any ancillary materials and equipment) is supported by the wire rope and tugger, the tugger may then be used to lower the diving board 111 until the holes 156a, 156b and 156c of the shear plates 152, the side plates 153, and the lower clamp section 150b, respectively, are substantially aligned. Furthermore, the diving board 111 may at this point be substantially aligned with and parallel to the plane 105p (see
As a result, the subject matter of the present disclosure provides details of various aspects of impact load absorbing diving board assemblies that may be used in conjunction with the vertical pipe racking systems of portable land-based drilling rigs. Additionally, the present disclosure is also directed to methods of operating the various embodiments of impact absorbing diving board assemblies disclosed herein. Furthermore, while the embodiments outlined in the present disclosure may be specifically directed to assemblies and methods that comprise automatic and/or remotely operated pipe handling systems for portable land-based drilling rigs, the concepts disclosed herein may be equally applicable to vertical pipe racking systems that employ substantially manual pipe handling operations—e.g., wherein automatic and/or remotely operated pipe handling systems are not utilized—as well as to non-portable land-based drilling rigs and/or offshore drilling applications.
The particular embodiments disclosed above are illustrative only, as the invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. For example, the method steps set forth above may be performed in a different order. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the invention. Accordingly, the protection sought herein is as set forth in the claims below.
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