Background of the Disclosure

The present disclosure relates, in general, to reducing the application of a force by a first device on a second device, which force is due, at least in part, to the weight of the first device. In particular, the present disclosure relates to employing at least one actuator to effect the force application reduction. According to one aspect, the second device on which the force is applied may be a tubular member. According to another aspect, the first device may be a quill and the second device may be a tubular member that is part of a string of drill pipe or casing employed, or to be employed, in oil and gas exploration and production operations.

Brief Description of the Drawings

The present disclosure is best understood from the following detailed description when read with the accompanying figures. It is emphasized that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.

FIG. 1-1 is a perspective view of apparatus according to one or more aspects of the present disclosure.

FIG. 1-2 is another perspective view of the apparatus shown in FIG. 1-1 according to one or more aspects of the present disclosure, but depicts a different operational mode of the apparatus.

FIG. 2 is a schematic view of apparatus according to one or more aspects of the present disclosure.

FIG. 3-1 is a perspective view of apparatus during operation according to one or more aspects of the present disclosure.

FIG. 3-2 is another perspective view of the apparatus shown in FIG. 3-1 during operation according to one or more aspects of the present disclosure.

FIG. 4 is a schematic view of apparatus according to one or more aspects of the present disclosure.

FIG. 5 is a schematic view of apparatus according to one or more aspects of the present disclosure. Detailed Description

It is to be understood that the following disclosure provides many different embodiments, or examples, for implementing different features of various embodiments. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. Moreover, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed interposing the first and second features, such that the first and second features may not be in direct contact.

Referring to FIGS. 1-1 and 1-2, illustrated are perspective views of apparatus 10, which includes a bearing carrier 12 and a coupling 14 coupled thereto. In an exemplary embodiment, the coupling 14 is a split clamp, which is adapted to clamp into a groove formed in a tubular component (not shown), as will be discussed in further detail below. In an exemplary embodiment, the bearing carrier 12 is adapted to provide rotatable support and may include various components (not shown), such as an inner bearing ring, an outer bearing ring, bearing elements, and/or any combination thereof. The bearing carrier 12 is connected to arms 16 and 18 via swivel bearings 20 and 22, respectively, thereby connecting the coupling 14 to the arms 16 and 18. The bearing carrier 12 extends between the arms 16 and 18, which are spaced in a parallel relation. Slots 24 and 26 are formed through the arm 16, and slots 28 and 30 are formed through the arm 18. Planar bearing elements 32 and 34 are connected to the arms 16 and 18, respectively. In an exemplary embodiment, each of the planar bearing elements 32 and 34 is a plane or friction bearing including a material selected to minimize friction and to inhibit or prevent wear debris from increasing friction during operational use; such a material may include at least one plastic material, polyether ether ketone (PEEK), graphite-based material(s), polytetrafluoroethylene (PTFE), other non- metallic material, other friction bearing material, or any combination thereof.

Slots 36 and 38 are formed through the planar bearing element 32 so that at least portions of the slots 36 and 38 overlap at least portions of the slots 24 and 26, respectively. In an exemplary embodiment, as shown in FIG. 1-1, the outer peripheries of the slots 36 and 38 conform to the outer peripheries of the slots 24 and 26, respectively. Likewise, slots 40 and 42 are formed through the planar bearing element 34 so that at least portions of the slots 40 and 42 overlap at least portions of the slots 28 and 30, respectively. In an exemplary embodiment, as shown in FIG. 1-2, the outer peripheries of the slots 40 and 42 conform to the outer peripheries of the slots 28 and 30, respectively.

As shown in FIG. 1-1, pins 44 and 46 extend from a shield retainer 48, and through the slots 24 and 26, respectively, as well as through the slots 36 and 38, respectively. Discshaped cam followers 50 and 52 are connected to the pins 44 and 46, respectively. The slots 24 and 36 define a region 54 in which the cam follower 50 is disposed. In an exemplary embodiment, one or more other lubricants (e.g., grease) may also be disposed in the region 54 to minimize friction between various components of the apparatus 10. Similarly, the slots 26 and 38 define a region 56 in which the cam follower 52 is disposed and, in an exemplary embodiment, one or more other lubricants may also be disposed in the region 56. Likewise, as shown in FIG. 1-2, pins 58 and 60 extend from a shield retainer 62, and through the slots 28 and 30, respectively, as well as through the slots 40 and 42, respectively. Disc-shaped cam followers 64 and 66 are connected to the pins 58 and 60, respectively. The slots 28 and 40 define a region 68 in which the cam follower 64 is disposed, and the slots 30 and 42 define a region 70 in which the cam follower 66 is disposed. In an exemplary embodiment, grease and/or one or more other lubricants may be disposed in each of the regions 68 and 70. In an exemplary embodiment, each of the pins 44, 46, 58 and 60 is a fastener, such as a bolt.

As shown in FIGS. 1-1 and 1-2, actuators 72 and 74 are connected to the arms 16 and 18, respectively. More particularly, the actuator 72 includes a housing 72a and an elongated member, such as a rod 72b, extending out of the housing 72a. Likewise, the actuator 74 includes a housing 74a and an elongated member, such as a rod 74b, extending out of the housing 74a. The rods 72b and 74b are connected to the arms 16 and 18, respectively.

Mounting brackets 76 and 78 are connected to the housings 72a and 74a, respectively. Under conditions to be described below, the actuators 72 and 74 controllably actuate the rods 72b and 74b, respectively, causing the rods 72b and 74b to extend out of the housings 72a and 74a, respectively, as shown in FIG. 1-1, and to retract into the housings 72a and 74a, respectively, as shown in FIG 1-2. As a result of the actuation of the rods 72b and 74b, the bearing carrier 12, the coupling 14, the arms 16 and 18, and the planar bearing elements 32 and 34 move, relative to the shield retainers 48 and 62, the cam followers 50, 52, 64 and 66, and the pins 44, 46, 58 and 60. In several exemplary embodiments, each of the actuators 72 and 74 is, includes, or is part of, a hydraulic actuator, an electromagnetic actuator, a pneumatic actuator, a linear actuator, and/or any combination thereof.

Referring to FIG. 2, illustrated is a schematic view of the apparatus 10. As shown in FIG. 2, the actuators 72 and 74 are hydraulic actuators, and the housings 72a and 74a are cylinder housings. The housings 72a and 74a define internal regions 72c and 74c, respectively. Heads, such as pistons 72d and 74d, are disposed in the internal regions 72c and 74c, respectively. The rods 72b and 74b are connected to the pistons 72d and 74d, respectively. The piston 72d defines on either side thereof region portions 72ca and 72cb of the region 72c. Likewise, the piston 74d defines on either side thereof region portions 74ca and 74cb of the region 74c.

A pressurized fluid source 80 is, or includes, a hydraulic accumulator 82, which is in fluid communication with each of the region portions 72ca and 74ca. A control valve 84 is in fluid communication with the hydraulic accumulator 82. In an exemplary embodiment, the control valve 84 is a two position, two way valve. A one-way valve 86 is in fluid

communication with, and fluidically disposed between, the control valve 84 and the hydraulic accumulator 82. A pump 88 is in fluid communication with the control valve 84. A fluid reservoir 90 is in fluid communication with the pump 88. A pressurized fluid source 92 is in fluid communication with each of the region portions 72cb and 74cb. In an exemplary embodiment, the pressurized fluid source 92 is a source of pressurized air. A control valve 94 is in fluid communication with, and fluidically disposed between, the pressurized fluid source 92 and each of the region portions 72cb and 74cb. In an exemplary embodiment, the control valve 94 is a multi-way valve.

A controller 96 is operably coupled to at least the control valves 84 and 94. The controller 96 includes a computer processor 96a and a computer readable medium 96b operably coupled thereto. Instructions accessible to, and executable by, the computer processor 96a are stored on the computer readable medium 96b. In an exemplary embodiment, the controller 96 may include one or more programmable logic controllers (PLCs). In an exemplary embodiment, the controller 96 may include a plurality of controllers, the computer processor 96a may include a plurality of computer processors, and/or the computer readable medium 96b may include a plurality of computer readable mediums. In an exemplary embodiment, the controller 96 may be located at a single location or distributed throughout a plurality of locations. In an exemplary embodiment, the computer readable medium 96b may include one or more databases and/or one or more data structures stored therein. In several exemplary embodiments, the computer processor 96a may include, for example, one or more of the following: a programmable general purpose controller, an application specific integrated circuit (ASIC), other controller devices, and/or any combination thereof.

Referring to FIGS. 3-1 and 3-2, illustrated are perspective views of the apparatus 10 during its operation. As shown in FIGS. 3-1 and 3-2 with continuing reference to FIGS. 1-1, 1-2 and 2, a tubular component 98 is engaged with the coupling 14. In an exemplary embodiment, the coupling 14 is a split clamp that clamps into an annular groove 98a formed in the outside surface of the tubular component 98, thereby engaging the tubular component 98. In another exemplary embodiment, the coupling 14 may be another type of clamp, collar or connection that engages and grips the tubular component 98 without employing the annular groove 98a. The tubular component 98 extends through the coupling 14 and the bearing carrier 12. A structural member 100 extends between the actuators 72 and 74, which are connected to the structural member 100 via the mounting brackets 76 and 78, respectively. The pins 44 and 46 are connected to the structural member 100, thereby connecting the shield retainer 48 to the structural member 100. Likewise, the pins 58 and 60 are connected to the structural member 100, thereby connecting the shield retainer 62 to the structural member 100. The structural member 100 extends between the planar bearing elements 32 and 34. In an exemplary embodiment, the planar bearing elements 32 and 34 slidably engage the structural member 100. The hydraulic accumulator 82 is connected to the structural member 100. The bearing carrier 12 allows the tubular component 98 to rotate with respect to the structural member 100. In an exemplary embodiment, instead of, or in addition to the structural member 100, the actuators 72 and 74 may be connected to one or more other structural members.

In operation, in an exemplary embodiment, the tubular component 98 and the structural member 100 may be suspended in the air, and/or may be suspended in water in, for example, a sea-based operation. During this suspension, the tubular component 98 is permitted to move, relative to the structural member 100, in a downward direction as viewed in FIG. 3-1 and indicated by an arrow 102. In several exemplary embodiments, the tubular member 98 may undergo no movement at all, almost no movement, or negligible movement. In several exemplary embodiments, the movement of the tubular component 98 may range from negligible movement up to about 6 inches of movement, about 12 inches of movement, or about 24 inches of movement.

As shown in FIG. 3-1, to the extent that the tubular component 98 moves in the direction indicated by the arrow 102, the rods 72b and 74b, the arms 16 and 18, the planar bearing elements 32 and 34, the bearing carrier 12, and the coupling 14 also move, relative to the structural member 100 and the housings 72a and 74a, in the direction indicated by the arrow 102. The bearing carrier 12 continues to rotatably support the tubular component 98. The cam followers 50, 52, 64 and 66, and the pins 44, 46, 58 and 60, guide the arms 16 and 18 during the movement of the arms 16 and 18 in the direction indicated by the arrow 102. The cam followers 50, 52, 64 and 66, the pins 44, 46, 58 and 60, and the planar bearing elements 32 and 34, provide bearing support, positioning, and stops during the movement of the arms 16 and 18 in the direction indicated by the arrow 102. The shield retainer 48 protects the cam followers 50 and 52 from debris, and the shield retainer 62 protects the cam followers 64 and 66 from debris.

In response to permitting the tubular component 98 to move in the direction indicated by the arrow 102, a force is applied, in the direction indicated by the arrow 102, against a tubular member (not shown), which is spaced from the tubular component 98 in the direction indicated by the arrow 102. The force applied in the direction indicated by the arrow 102 is due, at least in part, to the weight of the tubular component 98 and the ability of the tubular component 98 to move relative to the structural member 100. The force applied in the direction indicated by the arrow 102 may also be due to additional components hanging below the tubular component 98.

To reduce the force applied in the direction indicated by the arrow 102, the hydraulic accumulator 82 passively supplies hydraulic fluid to each of the region portions 72ca and 74ca, thereby supplying a substantially constant pressure to each of the region portions 72ca and 74ca. As a result, forces are applied against the pistons 72d and 74d in a direction indicated by an arrow 104, which is opposite to the direction indicated by the arrow 102. The arms 16 and 18 transfer to the rods 72b and 74b, respectively, at least respective portions of the force applied in the direction indicated by the arrow 102; however, these transferred portions of the force applied in the direction indicated by the arrow 102 are counteracted by the forces applied against the pistons 72d and 74d in the direction indicated by the arrow 104.

In response to the forces against the pistons 72d and 74d in the direction indicated by the arrow 104, the tubular component 98 rises in the direction indicated by the arrow 104. More particularly, the rods 72b and 74b retract into the housings 72a and 74a, respectively, causing the arms 16 and 18, the planar bearing elements 32 and 34, the bearing carrier 12, the coupling 14, and thus the tubular component 98, to rise in the direction indicated by the arrow 104, as shown in FIG. 3-2. As a result of the lifting of the tubular component 98, the force applied in the direction 102, which is due at least in part to the weight of the tubular component 98, is at least reduced or partially counteracted. Thus, the effective weight of the tubular component 98, or any assembly of which the tubular component 98 may be a part, is reduced.

As shown in FIG. 3-2, to the extent that the tubular component 98 moves in the direction indicated by the arrow 104, the rods 72b and 74b, the arms 16 and 18, the planar bearing elements 32 and 34, the bearing carrier 12, and the coupling 14 also move, relative to the structural member 100 and the housings 72a and 74a, in the direction indicated by the arrow 104. The bearing carrier 12 continues to rotatably support the tubular component 98. The cam followers 50, 52, 64 and 66, and the pins 44, 46, 58 and 60, guide the arms 16 and 18 during the movement of the arms 16 and 18 in the direction indicated by the arrow 104. The cam followers 50, 52, 64 and 66, the pins 44, 46, 58 and 60, and the planar bearing elements 32 and 34, provide bearing support, positioning, and stops during the movement of the arms 16 and 18 in the direction indicated by the arrow 104. The shield retainer 48 protects the cam followers 50 and 52 from debris, and the shield retainer 62 protects the cam followers 64 and 66 from debris.

In several exemplary embodiments, the force in the direction indicated by the arrow 102 may be applied to the tubular member to threadably engage (or make-up) the tubular member with another tubular member located therebelow to form, or continue to form, a string of drill pipe or casing. Alternatively, in several exemplary embodiments, the force in the direction indicated by the arrow 102 may be applied to threadably disengage (or breakout) the tubular member from another tubular member located therebelow. By employing the apparatus 10 to reduce the effective weight of the tubular component 98 or any assembly of which the tubular component 98 may be a part, the risk or potential of damaging threads is reduced during, for example, threadably engaging the tubular member with another tubular member, or threadably disengaging the tubular member from the other tubular member. As a result, careful make-up or break-out of two tubular members can be facilitated.

In several exemplary embodiments, the tubular component 98 may be part of a quill of a top drive, the structural member 100 may be part of a back up wrench (BUW) of the top drive, the top drive may be suspended in the air (or water), and the quill (including the tubular component 98) may be movable, relative to the BUW (including the structural member 100), during the suspension of the top drive and the operation of the apparatus 10, which operates in the above-described manner to reduce the effective weight of the quill.

In an exemplary embodiment, during operation of the apparatus 10, the hydraulic accumulator 82 is pre-charged to provide a desired minimum lifting force in the direction indicated by the arrow 104. To maintain this charge, the control valve 84 selectively supplies hydraulic fluid to the hydraulic accumulator 82, which hydraulic fluid is pumped from the fluid reservoir 90 by the pump 88. The one-way valve 86 permits the flow of hydraulic fluid from the control valve 84 to the hydraulic accumulator 82, and prevents backflow of the hydraulic fluid from the hydraulic accumulator 82 to the control valve 84.

In an exemplary embodiment, during operation of the apparatus 10, the control valve 94 selectively supplies a fluid, such as air, to each of the region portions 72cb and 74cb. As a result, forces in the direction indicated by the arrow 102 are applied to the pistons 72d and 74d. By employing the control valve 84 to control the supply of hydraulic fluid to the region portions 72ca and 74ca, and employing the control valve 94 to control the supply of air to the region portions 72cb and 74cb, the rods 72b and 74b may be placed at a predetermined position along a linear axis 106 that extends in the direction indicated by the arrows 102 and 104. Therefore, the arms 16 and 18, and thus the tubular component 98, may also be placed at respective predetermined positions along the linear axis 106.

In an exemplary embodiment, the controller 96 controls the operation of at least the control valves 84 and 94 to controllably place at least the rods 72b and 74b, the arms 16 and 18, and the tubular component 98, at respective predetermined positions along the linear axis 106. In an exemplary embodiment, the controller 96 controls the operation of at least the control valves 84 and 94 to control the speed or rate of displacement of at least the rods 72b and 74b, the arms 16 and 18, and the tubular component 98 along the linear axis 106 by, for example, controlling the rate at which fluid is introduced into the region portions 72ca, 72cb, 74ca and 74cb. In an exemplary embodiment, the computer processor 96a executes instructions stored on the computer readable medium 96b to carry out the above-described operation of the apparatus 10.

Referring to FIG. 4, illustrated is a schematic view of the apparatus 10. As shown in FIG. 4, the hydraulic accumulator 82 is omitted from the pressurized fluid source 80. Instead of including the hydraulic accumulator 82, the pressurized fluid source 80 includes a relieving regulator 108 in fluid communication with, and fluidically disposed between, the pump 88 and each of the region portions 72ca and 74ca. The control valve 84 is in fluid communication with, and fluidically disposed between, the relieving regulator 108 and the pump 88. The one-way valve 86 is in fluid communication with, and fluidically disposed between, the relieving regulator 108 and the control valve 84.

Position sensors 110 and 112 are operably coupled to the actuators 72 and 74, respectively. The controller 96 is operably coupled to each of the position sensors 110 and 112. In an exemplary embodiment, the position sensors 110 and 112 are part of, and/or integrated within, the actuators 72 and 74, respectively. In an exemplary embodiment, as shown in FIG. 4, each of the position sensors 110 and 112 is, includes, or is part of, a linear variable displacement transformer (LVDT) transducer. In an exemplary embodiment, the position sensors 110 and 112 are LVDT transducers, which are part of, and/or integrated within, the actuators 72 and 74, respectively. In several exemplary embodiments, instead of, or in addition LVDT transducers, the position sensors 110 and 112 may include one or more other types of position sensors such as potentiometers, magnetic sensors, other types of transducers, etc.

With continuing reference to FIG. 4, the operation of the apparatus 10 with the pressurized fluid source 80 as shown in FIG. 4, as well as with the position sensors 110 and 112, is substantially similar to the operation of the apparatus 10 described above in connection with FIGS. 2, 3-1 and 3-2, except in two respects, namely the supply of hydraulic fluid to the region portions 72ca and 74ca, as well as the operation of the controller 96.

With continuing reference to FIG. 4, with respect to the supply of hydraulic fluid to the region portions 72ca and 74ca during the operation of the apparatus 10, instead of the hydraulic accumulator 82 passively supplying a substantially constant pressure to each of the region portions 72ca and 74ca, the pump 88 actively supplies a hydraulic fluid to the region portions 72ca and 74ca, thereby supplying a substantially constant pressure to each of the region portions 72ca and 74ca. One or both of the control valve 84 and the relieving regulator 108 selectively supply the hydraulic fluid to the region portions 72ca and 74ca, and the one-way valve 86 permits flow of hydraulic fluid from the pump 88 to the relieving regulator 108, and prevents backflow of the hydraulic fluid from the relieving regulator 108 towards the pump 88.

With continuing reference to FIG. 4, with respect to the operation of the controller 96 during the operation of the apparatus 10, the position sensor 110 measures the linear displacement, along the axis 106, of at least one of the piston 72d, the rod 72b and the arm 16. In an exemplary embodiment, the respective linear displacements, along the axis 106, of the piston 72d, the rod 72b and the arm 16 are substantially equal and thus the measurement of the linear displacement of one of the piston 72d, the rod 72b and the arm 16 is an effective measurement of the respective linear displacements of the other two of the piston 72d, the rod 72b and the arm 16. Likewise, the position sensor 112 measures the linear displacement, along the axis 106, of at least one of the piston 74d, the rod 74b and the arm 18. In an exemplary embodiment, the respective linear displacements, along the axis 106, of the piston 74d, the rod 74b and the arm 18 are substantially equal and thus the measurement of the linear displacement of one of the piston 74d, the rod 74b and the arm 18 is an effective measurement of the respective linear displacements of the other two of the piston 74d, the rod 74b and the arm 18. Each of the position sensors 110 and 112 sends to the controller 96 one or more signals corresponding to one or more of these measured linear displacements.

Therefore, the position sensors 110 and 112 provide feedback to the controller 96, which employs the feedback to control one or more of the relieving regulator 108, the control valve 84 and the control valve 94 in order to place or maintain at least the rods 72b and 74b, and the arms 16 and 18, at respective predetermined positions along the linear axis 106.

In an exemplary embodiment, the pressurized fluid source 92 and the control valve 94 may be omitted from the apparatus 10.

In an exemplary embodiment, the hydraulic accumulator 82 may be included in the pressurized fluid source 80 illustrated in FIG. 4, and may be fluidically disposed at, for example, the location of the relieving regulator 108.

Referring to FIG. 5, illustrated is a schematic view of apparatus 114 demonstrating one or more aspects of the present disclosure. The apparatus 114 demonstrates an exemplary environment in which the apparatus 10 or portions thereof shown in one or more of FIGS. 1- 1, 1-2, 2, 3-1, 3-2 and 4 and/or other apparatus within the scope of the present disclosure may be implemented.

The apparatus 114 is or includes a land-based drilling rig. However, one or more aspects of the present disclosure are applicable or readily adaptable to any type of drilling rig, such as jack-up rigs, semisubmersibles, drill ships, coil tubing rigs, and casing drilling rigs, among others.

The apparatus 114 includes a mast 116 supporting lifting gear above a rig floor 117. The lifting gear includes a crown block 118 and a traveling block 120. The crown block 118 is coupled at or near the top of the mast 116, and the traveling block 120 hangs from the crown block 118 by a drilling line 122. The drilling line 122 extends from the lifting gear to draw-works 124, which is configured to reel the drilling line 122 out and in to cause the traveling block 120 to be lowered and raised relative to the rig floor 117.

A hook 126 may be attached to the bottom of the traveling block 120. A top drive

128 may be suspended from the hook 126, and may include a quill 130. The quill 130 may extend downward, as viewed in FIG. 5, and may be attached to a saver sub 132, which may be attached to a tubular lifting device 134. The quill 130 may include the tubular component 98 shown in FIGS. 3-1 and 3-2, with which the apparatus 10 is engaged as described above. The top drive 128 may include a back up wrench (BUW) 135, which may include the structural member 100 shown in FIGS. 3-1 and 3-2, to which the apparatus 10 is connected as described above.

As shown in FIG. 5, the tubular lifting device 134 can be engaged with a drill string 136 suspended within and/or above a wellbore 138. The drill string 136 may include one or more tubular members 140, the majority of which are interconnected to one another and one of which may be either threadably disengaged from, or threadably engaged with, another of the tubular members 140. The tubular members 140 may be part of a string of drill pipe or casing. It should be understood that various other types of tubular members, or tubulars, can often be substituted depending on the desired operation. In addition to the tubular members 140, the drill string 136 may include other components. One of the tubular members 140 may be the tubular member to which the force is applied in the direction indicated by the arrow 102 in FIGS. 3-1 and 3-2, the force being due, at least in part, to the weight of at least the quill 130, including the weight of at least the tubular component 98; that is, the force that is reduced as a result of the above-described operation of the apparatus 10. As shown in FIG. 5, one or more pumps 142 may deliver drilling fluid to the drill string 136 through a hose or other conduit 144, which may be connected to the top drive 128. The drilling fluid may pass through a central passage of the tubular lifting device 134.

In an exemplary embodiment, the top drive 128, quill 130 and saver sub 132 may not be utilized between the hook 126 and the tubular lifting device 134, such as where the tubular lifting device 134 is coupled directly to the hook 126, or where the tubular lifting device 134 is coupled to the hook 126 via other components.

In several exemplary embodiments, instead of a drilling rig, the apparatus 114 may be any device that requires reducing the effective weight of a structure being moved or used in an operation where the structure engages, or causes another structure to engage, a delicate, fragile, or easily-damaged component or portion thereof (such as a threaded connection), so that the weight reduction reduces, minimizes or prevents damage to the component or portion thereof.

In view of all of the above and the figures, one of ordinary skill in the art will readily recognize that the present disclosure introduces an apparatus including a first actuator, including a first housing defining a first internal region; a first head disposed in the first internal region, the first head defining on either side thereof first and second portions of the first internal region; and a first elongated member connected to the first head and extending out of the first housing; a first arm connected to the first elongated member to transfer to the first elongated member at least a first portion of a first force applied in a first direction by at least the weight of at least a tubular component; and a first pressurized fluid source in fluid communication with the first portion of the first internal region to apply a second force against the first head in a second direction that is opposite the first direction. According to one aspect, the apparatus includes the tubular component. According to another aspect, the apparatus includes a top drive, which includes a quill, wherein the tubular component is part of the quill; and a structural member to which the first housing is connected; wherein at least the quill, the first arm, the first elongated member and the first head are movable, relative to the structural member and the first housing, in the first and second directions. According to yet another aspect, the first actuator is a hydraulic cylinder, the first housing is a cylinder housing, the first head is a piston, and the first elongated member is a rod. According to still yet another aspect, the first pressurized fluid source includes a hydraulic accumulator to passively supply a substantially constant pressure to the first portion of the first internal region so that the second force is substantially constant and at least partially counteracts the first force. According to still yet another aspect, the apparatus includes a second pressurized fluid source in fluid communication with the second portion of the first internal region to apply a third force against the first head in the first direction to place the first arm, relative to the first housing, at a predetermined position along a linear axis that extends in the first and second directions. According to still yet another aspect, the first pressurized fluid source is a hydraulic accumulator; and the apparatus further includes a first control valve in fluid communication with the hydraulic accumulator to selectively supply a first fluid to the hydraulic accumulator; a one-way valve to permit flow of the first fluid from the first control valve to the hydraulic accumulator and to prevent backflow of the first fluid from the hydraulic accumulator to the first control valve; and a second control valve in fluid communication with, and fluidically disposed between, the second pressurized fluid source and the second portion of the first internal region to selectively supply a second fluid to the second portion of the first internal region. According to still yet another aspect, the apparatus includes a controller operably coupled to at least the first and second control valves to controllably place the first arm at the predetermined position. According to still yet another aspect, the apparatus includes a position sensor operably coupled to the first actuator to measure a linear displacement of the first arm along the linear axis; wherein the position sensor is operably coupled the controller to provide feedback to the controller to place or maintain the first arm at the predetermined position. According to still yet another aspect, the first pressurized fluid source includes a pump to actively supply a substantially constant pressure to the first portion of the first internal region so that the second force is substantially constant and at least partially counteracts the first force. According to still yet another aspect, the first pressurized fluid source includes a relieving regulator in fluid communication with, and fluidically disposed between, the pump and the first portion of the first internal region to selectively supply a first fluid to the first portion of the first internal region; and a one-way valve to permit flow of the first fluid from the pump to the relieving regulator and to prevent backflow of the first fluid from the relieving regulator towards the pump. According to still yet another aspect, the apparatus further includes a second pressurized fluid source in fluid communication with the second portion of the first internal region to apply a third force against the first head in the first direction to place the first arm, relative to the first housing, at a predetermined position along a linear axis that extends in the first and second directions; and a control valve in fluid communication with, and fluidically disposed between, the second pressurized fluid source and the second portion of the first internal region to selectively supply a second fluid to the second portion of the first internal region. According to still yet another aspect, the apparatus includes a controller operably coupled to at least the relieving regulator and the control valve to controllably place the first arm at the

predetermined position. According to still yet another aspect, the apparatus includes a position sensor operably coupled to the first actuator to measure a linear displacement of the first arm along the linear axis; wherein the position sensor is operably coupled to the controller to provide feedback to the controller to place or maintain the first arm at the predetermined position. According to still yet another aspect, the apparatus includes a bearing carrier connected to the first arm to rotatably support the tubular component; a first slot formed through the first arm; a first planar bearing element connected to the first arm; a second slot formed through the first planar bearing element, wherein at least a portion of the second slot overlaps at least a portion of the first slot; and a first pin extending through the first and second slots; wherein the first arm and the first planar bearing element are movable, relative to the first pin, in the first and second directions. According to still yet another aspect, the apparatus includes a second actuator, including a second housing defining a second internal region; a second head disposed in the second internal region, the second head defining on either side thereof first and second portions of the second internal region; and a second elongated member connected to the second head and extending out of the second housing; a second arm connected to each of the bearing carrier and the second elongated member to transfer to the second elongated member at least a second portion of the first force applied in the first direction by at least the weight of at least the tubular component, wherein the bearing carrier extends between the first and second arms; a third slot formed through the second arm; a second planar bearing element connected to the second arm; a fourth slot formed through the second planar bearing element, wherein at least a portion of the fourth slot overlaps at least a portion of the third slot; a second pin extending through the third and fourth slots; and a structural member to which the first and second pins, and the first and second housings, are connected; wherein the first pressurized fluid source is in fluid communication with the first portion of the second internal region to apply a fourth force against the second head in the second direction; and wherein the bearing carrier, the first and second arms, the first and second planar bearing elements, the first and second elongated members, and the first and second heads, are movable, relative to the structural member, the first and second housings, and the first and second pins, in the first and second directions.

The present disclosure also introduces an apparatus including a coupling to engage a quill having a weight; an arm connected to the coupling and to which a first force is applied in a first direction by at least a portion of the weight of the quill; and an actuator connected to the arm to apply thereto a second force to at least counteract the first force. According to one aspect, the apparatus includes a bearing carrier rotatably supporting the quill, wherein the coupling is coupled to the bearing carrier. According to another aspect, the arm is a first arm and the actuator is a second actuator, and wherein the apparatus further includes a second arm connected to the coupling and to which a third force is applied in the first direction by at least a portion of the weight of the quill, wherein the coupling and the bearing carrier extend between the first and second arms; and a second actuator connected to the second arm to apply to the second arm a fourth force to at least counteract the first and third forces when in combination with the second force. According to yet another aspect, the apparatus includes first and second slots formed through the first and second arms, respectively; first and second planar bearing elements connected to the first and second arms, respectively; third and fourth slots formed through the first and second planar bearing elements, respectively, wherein at least portions of the third and fourth slots overlap at least portions of the first and second slots, respectively; and first and second pins extending through the first and third slots, and the second and fourth slots, respectively; wherein at least the coupling, the bearing carrier, the first and second arms, and the first and second planar bearing elements are movable, relative to the first and second pins, in the first direction and a second direction opposite thereto. According to still yet another aspect, the apparatus includes the quill, wherein the quill is engaged with the coupling and is rotatably supported by the bearing carrier.

According to still yet another aspect, the apparatus includes a top drive, including the quill; and a structural member to which the first and second actuators are connected; wherein at least the quill, the coupling, the bearing carrier, and the first and second arms are movable, relative to the structural member, in the first direction and a second direction opposite thereto.

The present disclosure also introduces a method including suspending a tubular component and a structural member; permitting the tubular component to move, relative to the structural member, in a first direction while continuing to suspend the tubular component and the structural member; and reducing a first force applied in the first direction against a tubular member in response to permitting the tubular component to move in the first direction, including applying a second force against the tubular component in a second direction that is opposite the first direction. According to one aspect, the first force applied in the first direction against the tubular member is due, at least in part, to the weight of the tubular component and the ability of the tubular component to move relative to the structural member. According to another aspect, the tubular component is part of a quill of a top drive; and wherein the tubular member is, or is to be, part of a string of drill pipe or casing.

According to yet another aspect, applying the second force against the tubular component in the second direction includes passively supplying a substantially constant pressure to a first internal region, through which an elongated member extends, the elongated member being connected to the tubular component. According to still yet another aspect, the method includes applying a third force in the first direction against a head connected to the elongated member to place the tubular component, relative to the structural member, at a predetermined position along a linear axis that extends in the first and second directions. According to still yet another aspect, the method includes employing a position sensor to measure the linear displacement of the tubular component, relative to the structural member, along the linear axis; and providing feedback to a controller operably coupled to the position sensor to controllably place or maintain the tubular component at the predetermined position.

According to still yet another aspect, applying the second force against the tubular component in the second direction includes actively supplying a substantially constant pressure to a first internal region, through which an elongated member extends, the elongated member being connected to the tubular component. According to still yet another aspect, the method includes applying a third force in the first direction against a head connected to the elongated member to place the tubular component, relative to the structural member, at a predetermined position along a linear axis that extends in the first and second directions. According to still yet another aspect, the method includes employing a position sensor to measure the linear displacement of the tubular component, relative to the structural member, along the linear axis; and providing feedback to a controller operably coupled to the position sensor to controllably place or maintain the tubular component at the predetermined position.

According to still yet another aspect, the method includes rotatably supporting the tubular component; and guiding an arm connected to the tubular component during movement of the tubular component, relative to the structural member, in the first or second direction.

The foregoing outlines features of several embodiments so that a person of ordinary skill in the art may better understand the aspects of the present disclosure. Such features may be replaced by any one of numerous equivalent alternatives, only some of which are disclosed herein. One of ordinary skill in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. One of ordinary skill in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions and alterations herein without departing from the spirit and scope of the present disclosure.

The Abstract at the end of this disclosure is provided to comply with 37 C.F.R.

§ 1.72(b) to allow the reader to quickly ascertain the nature 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. Moreover, 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 word "means" together with an associated function.