Patent Publication Number: US-11035348-B2

Title: Reciprocating pumps having a pivoting arm

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims benefit of U.S. Provisional Patent Application No. 62/723,885 filed Aug. 28, 2018, and entitled “Pump Assemblies and Pumping Systems Incorporating Pump Assemblies,” which is hereby incorporated herein by reference in its entirety for all purposes. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     BACKGROUND 
     This disclosure relates generally to systems for pressurizing a working fluid. More particularly, some embodiments of this disclosure relate to pumping systems that include one or more direct drive pump assemblies for pressurizing a working fluid for subsequent injection into a subterranean wellbore. 
     To form an oil or gas well, a bottom hole assembly (BHA), including a drill bit, is coupled to a length of drill pipe to form a drill string. The drill string is then inserted downhole, where drilling commences. During drilling, fluid (or “drilling mud”) is circulated down through the drill string to lubricate and cool the drill bit as well as to provide a vehicle for removal of drill cuttings from the borehole. After exiting the bit, the drilling fluid returns to the surface through an annulus formed between the drill string and the surrounding borehole wall (or a casing pipe lining the borehole wall). Mud pumps are commonly used to deliver drilling fluid to the drill string during drilling operations. Many conventional mud pumps are of a triplex configuration, having three piston-cylinder assemblies driven out of phase by a common crankshaft and hydraulically coupled between a suction manifold and a discharge manifold. During operation of the mud pump, each piston reciprocates within its associated cylinder. As the piston moves to expand the volume within the cylinder, drilling fluid is drawn from the suction manifold into the cylinder. After the piston reverses direction, the volume within the cylinder decreases and the pressure of drilling fluid contained with the cylinder increases. When the piston reaches the end of its stroke, pressurized drilling fluid is exhausted from the cylinder into the discharge manifold. While the mud pump is operational, this cycle repeats, often at a high cyclic rate, and pressurized drilling fluid is continuously fed to the drill string at a substantially constant rate. 
     BRIEF SUMMARY 
     Some embodiments disclosed herein are directed to a pump assembly for pressurizing a working fluid. In an embodiment, the pump assembly includes a base, and a power end mounted to the base, the power end comprising an output shaft having an output shaft axis. In addition, the pump assembly includes a fluid end mounted to the base, the fluid end comprising a piston configured to reciprocate within the fluid end to pressurize the working fluid. Further, the pump assembly includes a transmission coupled to each of the power end and the fluid end. The transmission includes a carriage coupled to the piston and reciprocally coupled to the base. In addition, the transmission includes a pivoting arm pivotably coupled to the carriage at a first connection about a first pivot axis. The first pivot axis extends in a direction that is perpendicular to a direction of the output shaft axis. Wherein rotation of the output shaft about the output shaft axis is configured to cause the pivoting arm to pivot about the first pivot axis at the first connection and to cause the carriage to reciprocate relative to the base. 
     Other embodiments disclosed herein are directed to a pumping system. In an embodiment, the pumping system includes a suction manifold, a discharge manifold, and a plurality of pump assemblies configured to draw a working fluid from the suction manifold, pressurize the working fluid, and deliver the pressurized working fluid to the discharge manifold. Each of the plurality of pump assemblies includes a base, a power end mounted to the base, the power end comprising an output shaft having an output shaft axis. In addition, each of the pump assemblies includes a fluid end mounted to the base, the fluid end comprising a piston configured to reciprocate within the fluid end to pressurize the working fluid. Further, each of the pump assemblies includes a transmission coupled to each of the power end and the fluid end. The transmission includes a carriage coupled to the piston and reciprocally coupled to the base, and a pivoting arm pivotably coupled to the carriage at a first connection about a first pivot axis. The first pivot axis extends in a direction that is perpendicular to a direction of the output shaft axis. Wherein rotation of the output shaft about the output shaft axis is configured to cause the pivoting arm to pivot about the first pivot axis at the first connection and to cause the carriage to reciprocate relative to the base. 
     Embodiments described herein comprise a combination of features and characteristics intended to address various shortcomings associated with certain prior devices, systems, and methods. The foregoing has outlined rather broadly the features and technical characteristics of the disclosed embodiments in order that the detailed description that follows may be better understood. The various characteristics and features described above, as well as others, will be readily apparent to those skilled in the art upon reading the following detailed description, and by referring to the accompanying drawings. It should be appreciated that the conception and the specific embodiments disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes as the disclosed embodiments. It should also be realized that such equivalent constructions do not depart from the spirit and scope of the principles disclosed herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a detailed description of various exemplary embodiments, reference will now be made to the accompanying drawings in which: 
         FIG. 1  is a schematic view of an embodiment of a pumping system according to at least some embodiments; 
         FIG. 2  is a schematic view of an embodiment of a pump assembly for use within the pumping system of  FIG. 1  according to at least some embodiments; 
         FIG. 3  is a schematic, partial, side cross-sectional view of the transmission of the pump assembly of  FIG. 2 ; 
         FIGS. 4 and 5  are partial perspective views of the transmission of the pump assembly of  FIG. 2 ; 
         FIG. 6  is a partial perspective view of the transmission of another pump assembly for use within the pumping system of  FIG. 1  according to at least some embodiments; and 
         FIG. 7  is a schematic, partial cross-sectional view of the transmission of  FIG. 6 . 
     
    
    
     DETAILED DESCRIPTION 
     The following discussion is directed to various exemplary embodiments. However, one of ordinary skill in the art will understand that the examples disclosed herein have broad application, and that the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to suggest that the scope of the disclosure, including the claims, is limited to that embodiment. 
     The drawing figures are not necessarily to scale. Certain features and components herein may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in interest of clarity and conciseness. 
     In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . .” Also, the term “couple” or “couples” is intended to mean either an indirect or direct connection. Thus, if a first device couples to a second device, that connection may be through a direct connection of the two devices, or through an indirect connection that is established via other devices, components, nodes, and connections. In addition, as used herein, the terms “axial” and “axially” generally mean along or parallel to a given axis (e.g., central axis of a body or a port), while the terms “radial” and “radially” generally mean perpendicular to the given axis. For instance, an axial distance refers to a distance measured along or parallel to the axis, and a radial distance means a distance measured perpendicular to the axis. As used herein, the terms “gimbal,” “gimbal member,” and the like, refers to a pivoted support that allows the rotation of an object about an axis. 
     As previously described above, mud pumps, including multiple piston-cylinder assemblies driven out of phase by a common crankshaft, are typically used to deliver drilling fluid to a drill string during drilling operations. These pumps have a set footprint and configuration. Thus, if it is desired to increase the flow rate of drilling fluid above what the piston-cylinder assemblies can deliver, an additional mud pump must be installed, or another mud pump must be designed and fabricated that includes the appropriate number of piston-cylinder assemblies to provide the desired flow rate of drilling fluid. As a result, these conventional mud pumps are not easily adaptable to the changing specifications and needs of many drilling applications. In addition, adequate space must be provided at the drill site to accommodate not only the size of these mud pumps but also the set footprint thereof. 
     Accordingly, embodiments disclosed herein include pumping systems for pressurizing a working fluid (e.g., drilling fluid injected into a subterranean wellbore), that include a plurality of modular pump assemblies. As a result, the number and specific arrangement of the modular pump assemblies may be altered as desired to accommodate a specific flow rate, pressure, and spacing requirements of the drilling operation. 
     Referring now to  FIG. 1 , a pumping system  10  for pressurizing a working fluid (e.g., drilling mud) is shown. Pumping system  10  generally includes a suction manifold  12 , a discharge manifold  14 , and a plurality of pumping assemblies  100 . Suction manifold  12  is in fluid communication with a working fluid source (e.g., a mud pit), and discharge manifold  14  is in fluid communication with a fluid delivery point (e.g., a central throughbore of a drill string). Each pump assembly  100  is coupled to suction manifold  12  with a corresponding suction line  16 , and is coupled to discharge manifold  14  with a corresponding discharge line  18 , such that each pump assembly  100  is configured to receive fluids from suction manifold  12  via the corresponding suction line  16 , and emit pressurized fluid to one of the discharge manifolds  14  via the corresponding discharge line  18 . 
     Each pump assembly  100  includes a power end  109 , a transmission  120 , and a fluid end  60 . In this embodiment, power end  109  comprises a motor  110  including an output shaft  112 . Motor  110  may be any suitable motor or driver that is configured to actuate (e.g., rotate) an output shaft  118 , such as, for example, an electric motor, hydraulic motor, internal combustion engine, turbine, etc. In this embodiment, motor  110  comprises an electric motor  110 . 
     Transmission  120  comprises any suitable mechanism that is configured to translate the output from motor  110  into an input drive for fluid end  60 . For example, in this embodiment, motor  110  drives the rotation of output shaft  118 , and transmission  120  is configured to convert the rotational motion of output shaft  118  into a reciprocal motion for driving a piston  64  within fluid end  60  (note: in some embodiments, pistons  64  may be replaced with a plunger or other reciprocating member, thus, the term “piston” is used herein to include various designs of pistons, plungers, bladders, and other suitable reciprocating members for use within fluid end  60 ). While some specific embodiments of transmission  120  are discussed below, it should be appreciated that transmission  120  may comprise any suitable arrangement of gears, cams, sliders, carriages, or other components to affect the desired motion conversion between motor  110  and fluid end  60 . 
     Fluid end  60  defines a chamber  62  that receives piston  64  therein. Piston  64  is coupled to transmission  120  and is configured to reciprocate within chamber  62  and sealingly engage with the inner walls of chamber  62  to facilitate the pressurization and flow of a working fluid (e.g., drill mud) therein. Fluid end  60  includes a suction valve  15  and a discharge valve  17 . Suction valve  15  is configured to allow fluid flow into chamber  62  via suction line  16  when piston  64  withdrawn from chamber  62  (e.g., toward transmission  120 ) and the pressure within chamber  62  falls below a first predetermined level, but to prevent fluid from flowing out of chamber  62  into line  16 . Discharge valve  17  is configured to allow fluid to flow out of chamber  62  into discharge line  18  when piston  64  is advanced into chamber  62  (e.g., away from transmission  120 ) and the pressure within chamber  62  rises above a second predetermined level, but to prevent fluid from flowing into chamber  62  from discharge line  18 . While valves  15 ,  17  are merely shown schematically in  FIG. 1 , it should be appreciated that valves  15 ,  17  may be the same or similar to those disclosed in U.S. Pat. Nos. 8,220,496 and/or 8,714,193, the entire contents of each being incorporated herein by reference for all purposes. 
     Referring still to  FIG. 1 , pumping system  10  includes a plurality of suction valves  22  and discharge valves  24 . Each of the suction valves  22  is disposed along one of the suction lines  16  and each of the discharge valves  24  is disposed along one of the discharge lines  18 . Each of the valves  22 ,  24  is coupled to a central controller  50  through a corresponding connection  58 , which may be any suitable wired or wireless connection for communicating signals, such as, for example a cable, wire, fiber optic line, radio frequency (RF) connection, a WIFI connection, BLUETOOTH® connection, short wave communication signal, acoustic connection, etc. Controller  50  may include a processor and a memory, wherein each of the processor and memory may comprise one or more electrical circuits. The memory includes computer readable instructions for execution by the processor to provide all of the functionality of controller  50  disclosed herein. Each of the valves  22 ,  24  also includes a pair of sensors  26 ,  28  that are configured to sense whether the corresponding valve (e.g., valve  22 ,  24 ) is opened or closed (i.e., whether the valves  22 ,  24  are in an open position or a closed position, respectively). Specifically, one sensor  26  is configured to sense when the corresponding valve is in the open position (to thereby allow fluid to flow freely along the corresponding line  16 ,  18 ), and the other sensor  28  is configured to sense when the corresponding valve is in the closed position (to thereby prevent or restrict fluid flow along the corresponding line  16 ,  18 ). The sensors  26 ,  28  are each configured to communicate with controller  50  via connections  58  so that controller  50  may know whether each valve  16 ,  18  is in the open or closed position. In this embodiment, controller  50  is coupled to an external device  51 , which may comprise, for example, a display (e.g., a computer monitor) that is further configured to display information (e.g., a graphic) that shows which of the valves  22 ,  24  is in the open position and which of the valves  22 ,  24  is in the closed position. In addition, in some embodiments, controller  50  may be configured to actuate each of the valves  22 ,  24  between the open and closed positions. 
     Each pump assembly  100  includes a plurality of sensors that communicate with controller  50  to facilitate and optimize the control thereof during operations. For example, in this embodiment, each pump assembly  100  includes a rotary sensor  56  coupled to motor  110  and configured to measure or determine the rotational speed and/or direction of the output shaft  118 . In addition, each pump assembly  100  includes a linear displacement or position sensor  54  coupled to transmission  120  or fluid end  60  (in this embodiment, sensor  54  is coupled to transmission  120 ) and configured to measure or determine the position or displacement of piston  64  relative to some fixed point. Further, each pump assembly  100  includes a pressure sensor  52  coupled to fluid end  60  and configured to measure a pressure of the chamber  62  during operations. Each of the sensors  52 ,  54 ,  56  are coupled to controller  50  through a corresponding connection  58 , where connections  58  between sensors  52 ,  54 ,  56  and controller  50  are configured the same as the connections  58  between sensors  26 ,  28  and controller  50 . 
     In some embodiments, controller  50  drives motors  110  so that the pistons  64  of pump assemblies  100  operate in phase with one another but with a continuously variable angle or timing between them (e.g., via controller  50 ) to produce a relatively constant flow of pressurized working fluid to discharge manifold. Specifically, in this embodiment, because pumping system  10  includes two pump assemblies, the pistons  64  are operated approximately 180° out of phase with one another (i.e., so that as each piston  64  reaches its maximum extension during a discharge stroke, the other piston reaches its minimum extension during a suction stroke). However, it should be appreciated that the phase difference between pistons  64  of pump assemblies  100  will change as the number of pump assemblies  100  is increased or deceased (e.g., if three pump assemblies  100  are used, each piston  64  is operated approximately 120° out of phase with the other pistons  64 ). In some embodiments, controller  110  verifies and/or maintains the proper timing of the strokes of pistons  64  (e.g., to maintain the desired phase separation of pistons  64 ) by sensing the motor rotational speed and direction via rotary sensors  56  and correlating the measured rotational speed to the position of piston  64  via linear displacement or position sensors  54 . 
     For each pump assembly  100 , as motor  110  drives rotation of output shaft  118 , transmission  120  converts this rotational motion into a reciprocating motion so that piston  64  is repetitively driven between a suction stroke and a discharge stroke within chamber  62 . During a suction stroke of piston  64 , piston  64  is withdrawn toward transmission  120  such that the pressure within chamber  62  is reduced to draw in working fluid from line  16  via suction valve  15 . In addition, during a suction stroke, working fluid is prevented from flowing into chamber  62  by discharge valve  17 . Conversely, during a discharge stroke, piston  64  is driven or extended away from transmission  120 , such that the pressure within chamber  62  is increased to force fluid out of chamber  62  into discharge line  18  via discharge valve  17 . In addition, during a discharge stroke, working fluid is prevented from flowing out of chamber  62  into suction line  16  by suction valve  15 . 
     Specific embodiments of pump assemblies  100  will now be described in more detail. It should be appreciated that any one or more of these embodiments discussed below may be incorporated into pumping system  10  of  FIG. 1 . 
     Referring now to  FIG. 2 , embodiment of pump assembly  100  is shown. As previously described, pump assembly  100  includes power end  109 , transmission  120 , and fluid end  60 . In some embodiments, fluid end  60  may be the same as the fluid end embodiments disclosed in WO2017/123656. Pump assembly  100  may be referred to as a modular unit in that the components of pump assembly  100  may be easily disassembled, assembled, and/or interchanged with other similar components. This may facilitate transportation, design, maintenance, and replacement of pump assembly  100  and the components thereof during operations. 
     In the embodiment of  FIG. 2 , power end  109  includes both motor  110  and a reducer  114 . The reducer  114  is coupled between a shaft  112  of motor  110  and transmission  120 . In particular, reducer  114  includes a reducer gear assembly  116  that is coupled to shaft  112  and an output shaft  118  that engages with transmission  120 . Thus, in this embodiment output shaft  118  may be referred to as an “output shaft” of power end  109 . In this embodiment, reducer gear assembly  116  is configured to rotate output shaft  118  a fraction of the number of times that shaft  112  rotates. Specifically, in this embodiment, reducer gear assembly  116  is configured to rotate output shaft  118  one time for every sixteen rotations of shaft  112  of motor  110 . Thus, reducer gear assembly  116  works to reduce the rotational rate (e.g., in rotations per minute (rpm)) of shaft  112  of motor  110  and to increase the torque supplied to transmission  120  from that generated by motor  110  alone. It should be appreciated, that in some embodiments, no reducer  114  is included and shaft  112  of motor  110  couples directly to transmission  120  (such that shaft  112  may be referred to as an “output shaft” of power end  109  in these embodiments). In other embodiments, reducer gear assembly  116  is incorporated into motor  110  itself such that reducer gear assembly  116  would be disposed within an outer housing of motor  110  and output shaft  118  of reducer  114  would effectively be the output shaft of motor  110  itself. 
     Referring still to  FIG. 2 , pump assembly  100  also includes a base or frame  101  to support power end  109 , transmission  120 , and fluid end  60 . In this embodiment, base  101  includes a first or motor base  102 , and a second or transmission base  103  coupled to motor base  102 . Motor base  102  supports power end  109  including motor  112  and reducer  114 , while transmission base  103  supports transmission  120  and fluid end  60 . 
     Motor base  102  comprises a first end  102   a , and a second end  102   b  that is opposite first end  102   a . Similarly, transmission base  103  includes a first end  103   a , and a second end  103   a  that is opposite first end  103   a . Motor base  102  is coupled to the first end  103   a  of transmission base  103  at second end  102   b  via one or more mounting plates  106  that are disposed on first end  103   a  of transmission base  103 . Mounting plates  106  each include a plurality of holes or apertures  107  for receiving bolts or other connection members (e.g., screws, pins, rivets, etc.) therethrough. In addition, transmission base  103  includes a pair of vertically oriented support extensions  105  at second end  103   b  that form a frame for supporting fluid end  60  on base  103 . In this embodiment, a mounting plate  108  is coupled to extensions  105  and fluid end  60  is mounted to plate  107 . However, in other embodiments, fluid end  60  may be secured to extensions  105  without a mounting plate  108  (e.g., fluid end  60  may be secured to extensions  105  via separate bracket or other support member or may be directly mounted to extensions  105  without utilizing a separate support or mounting member). 
     Power end  109  may be decoupled from transmission  120  and bases  102 ,  103  may also be decoupled at mounting plates  106  so that power end  109  may be transported or maneuvered separately from transmission  120  and fluid end  60  on base  103 . In addition, fluid end  60  may be decoupled from base  103  and moved, repaired, replaced via the connection at plate  108  and beams  105 . Therefore, bases  102 ,  103  help to facilitate the modularity of pump assembly  100  by providing relatively simple attachment points between the components (e.g., specifically between motor  110  and reducer  114  and transmission  120 , and between transmission  120  and fluid end  60 ). 
     Referring now to  FIGS. 2 and 3 , transmission  120  provides a linkage between power end  109  and the fluid end  60  to drive reciprocation of piston  64  within fluid end  60  (e.g., see also  FIG. 1 ) to pressurize a working fluid as previously described above. Specifically, transmission  120  converts the rotational motion of output shaft  118  of reducer  114  (or output shaft of motor  112 ) into a reciprocal motion of the piston  64  within fluid end  60 . In this embodiment, transmission  120  includes an offset shaft assembly  122  coupled to output shaft  118 , a carriage  150  coupled to the piston  64 , a pivoting arm assembly  141  coupled to the carriage  150 , and a linking assembly  130  coupled between the offset shaft assembly  122  and pivoting arm assembly  141 . 
     Carriage  150  is coupled to piston  64  that is reciprocally disposed within fluid end  60  as previously described (see also  FIG. 1 ). During operations, carriage  150  is driven to reciprocate relative to transmission frame  103  by power end  109  via offset shaft assembly  122 , linking assembly  130 , and pivoting arm assembly  141 . As a result, the reciprocation of carriage  150  drives reciprocation of the piston  64 . As shown in  FIG. 3 , the reciprocation of carriage  150  may be facilitated and supported by one or more tracks  156  that are mounted to frame  103  (note: frame  103  is not shown in  FIG. 3  so as not to unduly complicate the figure). In some embodiments, carriage  150  may be similar to the carriages (or carriage assemblies) described in WO2017/123656. 
     Referring again to  FIG. 2 , offset shaft assembly  122  includes an offset collar member  123  and a shaft  128 . Offset collar member  123  is an elongate member having a first end  123   a , a second end  123   b  opposite the first end  123   a , a first throughbore  124 , and a second throughbore  125 . As shown in  FIG. 2 , first throughbore  124  is disposed more proximate to first end  123   a  than second end  123   b , and second throughbore  125  is disposed more proximate to second end  123   b  than first end  123   a.    
     Second throughbore  125  receives a first end  128   a  of shaft  128 , and first throughbore  124  receives an end of output shaft  118  of reducer  114 . In this embodiment output shaft  118  is mounted within throughbore  124  such that no relative rotation between shaft  118  and throughbore  124  is allowed (i.e., such that offset collar member  123  rotates with output shaft  118  during operation). In some embodiments, shaft  118  and throughbore  124  may include a corresponding keyed or splined connection. In other embodiments, output shaft  118  may include one or more facets or planar surfaces that interact with corresponding planar surfaces within throughbore  124  (e.g., output shaft  118  and throughbore  124  may include polygonal cross-sections). 
     In addition, in the embodiment of  FIG. 2 , offset collar member  123  includes a connector  126  at first end  123   a  that forms a portion (e.g., half) of first throughbore  124 . Connector  126  may be secured to the rest of offset collar member  123  about shaft  118  via a plurality of bolts  127  (or other suitable connection members (e.g., screws, pins, rivets, etc.). 
     Shaft  128  is an elongate member that includes first end  128   a  and a second end  128   b  opposite first end  128   a . First end  128   a  of shaft  128  is received within second throughbore  125  of offset collar member  123 , as previously described, such that shaft  128  may rotate freely relative to offset collar member  123  during operations. For example, one or more bearings (e.g., radial or spherical bearings—not shown) may be disposed within throughbore  125  to facilitate the relative rotation between shaft  128  and collar member  123 . 
     Referring again to  FIGS. 2 and 3 , in this embodiment, offset collar member  123  (or at least a portion thereof) extends outward from a central axis  115  of output shaft  118  at an angle (not specifically marked in  FIG. 2 ) that is between 0° and 90° (i.e., offset collar member  123  extends at an acute angle to axis  115  of output shaft  118 ). Thus, when first end  128   a  of shaft  128  is received through second throughbore  125 , shaft  128  extends along an axis  129  that is disposed at an angle θ to axis  115  of output shaft  118 . Axis  115  may be referred to herein as the output shaft axis  115 , and the axis  129  may be referred to herein as the offset shaft axis  129 . The angle θ may range between 0° and 90°. In some embodiments, the angle θ may range from 10° to 50°, or from 15° to 23°. In other embodiments, offset collar member  123  may extend radially outward (e.g., at 90°) from axis  115  of shaft  118 . 
     During operations, as output shaft  118  is rotated about axis  115 , offset collar  123  is also caused to rotate about axis  115  at throughbore  124  (e.g., due to the connection between shaft  118  and throughbore  124  as previously described above). As a result, second throughbore  125  and first end  128   a  of shaft  128  are also caused rotate about axis  115  such that axis  129  of shaft  128  traces a cone (not shown) that has sides extending at the angle θ relative to axis  115 . 
     Referring still to  FIGS. 2 and 3 , as previously described linking assembly  130  is coupled between each of the offset shaft assembly  122  and carriage  150 . In this embodiment, linking assembly  130  comprises a universal joint (U-joint) assembly  121  (or more simply “U-joint  121 ”), that is mounted to second end  128   b  of offset shaft  128  and is pivotably coupled to carriage  150  via a pivoting arm assembly  141 . 
     U-joint  121  includes a first gimbal member  132  and a second gimbal member  138  pivotably coupled to one another. First gimbal member  132  includes a base  134  and a pair of parallel extensions  136  extending from base  134  that define a recess  133  therebetween. Second end  128   b  of shaft  128  is engaged with base  134  such that first gimbal member  132  may not rotate relative to shaft  128 . Any suitable connection may be used between first gimbal member  132  and shaft  128 , such as, for example, threads, a flanged coupling, welding, clamps, etc. Each of the extensions  136  includes a throughbore  131  extending therethrough that are aligned with one another along a pivot axis  135 ′ extending across recess  133 . 
     Second gimbal member  138  includes a central body  138   a , a first pair of shafts  137   a ,  137   b , and a second pair of shafts  139   a ,  139   b . Each of the shafts  137   a ,  137   b  extend from a first pair of opposing sides of body  138   a  and each of the shafts  139   a ,  139   b  extend from a second pair of opposing sides of body  138   a . Central body  138   a  is received within recess  133  and the second pair of shafts  139   a ,  139   b  are pivotably inserted through throughbores  131  of projections  136 , such that shafts  139   a ,  139   b  are aligned along pivot axis  135 ′. Thus, body  138   a  of second gimbal member  138  may freely pivot about pivot axis  135 ′ relative to first gimbal member  132  due to the coupling between throughbores  131  and shafts  139   a ,  139   b . Any suitable bearing or similar coupling may be used between throughbores  131  and shafts  139   a ,  139   b  (e.g., radial and/or spherical bearings) to support the relative rotation therebetween. However, shafts  139   a ,  139   b  may be secured within throughbores  131 , such that axial movement of second gimbal member  138  relative to first gimbal member  132  along pivot axis  135 ′ is prevented (or at least restricted). 
     As best shown in  FIG. 2 , the first pair of shafts  137   a ,  137   b  of second gimbal member  138  are pivotably received within a pair of shaft mounts  145  mounted to transmission base  103  such that shafts  137   a ,  137   b  are disposed along a pivot axis  135 ″ that is orthogonal to pivot axis  135 ′. Only one shaft mount  145  is shown in  FIG. 2  (i.e., the other shaft mount  145  and the associated portion of base  103  for supporting the shaft mount  145  is hidden in  FIG. 2  so as to more clearly show the components of linking assembly  130 ). However, it should be appreciated that the un-depicted shaft mount  145  (and the portion of base  103  supporting shaft mount  145 ) would be the same as the depicted shaft mount  145  (and base support) in  FIG. 2 , and would be disposed on the opposing side of the linking assembly  130  from the depicted shaft mount (and base support). Body  138   a  of second gimbal member  138  may freely pivot relative to mounts  145  about pivot axis  135 ″. In addition, due to the connection between shafts  139   a ,  139   b  and throughbores  131  in projections  136 , first gimbal member  132  and second gimbal member  138  may both pivot together about pivot axis  135 ″ during operations. 
     Referring still to  FIGS. 2 and 3 , pivoting arm assembly  141  includes a sleeve member  140  and a pivoting arm  144 . Sleeve member  140  includes a sleeve  142  that receives shaft  139   b  extending from body  138   a . Pivoting arm  144  includes a first end  144   a , a second end  144   b  opposite first end  144   a , and a pair of connecting arms  146  extending from first end  144   a  that form a recess  147  extending therebetween. First end  144   a  of pivoting arm  144  is pivotably coupled sleeve member  140 , while second end  144   b  of pivoting arm  144  is pivotably coupled to carriage  150 . In particular, a first connection (e.g., a pinned coupling)  148  extends through each of the pivoting arm  144  and carriage assembly  152  proximate second end  144   b . In addition, sleeve member  140  is received within recess  147  between arms  146  and a second connection (e.g., a pinned connection)  149  extends between arms  146  and sleeve member  140 . Thus, pivoting arm  144  may pivot relative to carriage  150  about a pivot axis  143 ″ at first connection  148 , and pivoting arm  144  and sleeve member  140  may pivot relative to one another about a pivot axis  143 ′ at second connection  149 . In addition, as pivoting arm  144  and sleeve member  140  pivot relative to one another about axis  143 ′ about second connection  149 , sleeve  142  (and shaft  139   b  disposed therein) may be received within recess  147 . Pivot axes  143 ′,  143 ″ are parallel and radially offset from one another. In addition, each of the pivot axes  143 ′,  143 ″ are parallel to and radially offset from pivot axis  135 ″, and each of the pivot axes  143 ′,  143 ″ extending in directions that are perpendicular to the direction of axis  135 ′ and the direction of output shaft axis  115 . Moreover, each of the axes  143 ′,  143 ″,  135 ″ lie within vertically oriented planes that extend perpendicularly to a vertically oriented plane containing the output shaft axis  115  (assuming that base  101  is level on a support surface). 
     Referring now to  FIGS. 2-5 , during operations, output shaft  118  of reducer  116  is rotated about axis  115  by motor  110  as previously described, which further causes offset collar member  123  to rotate about axis  115 . The rotation of collar member  123  about axis  115  further causes shaft  128  to orbit about axis  115  and thereby trace a cone as previously described. The orbit of shaft  128  about axis  115  causes first gimbal member  132  to reciprocally pivot relative to second gimbal member  138  about pivot axis  135 ′ (via the relative pivoting between shafts  139   a ,  139   b  and throughbores  131  in extensions  136  as previously described above). Simultaneously, the orbit of shaft  128  causes first and second gimbal members  132 ,  138  to reciprocally pivot together about pivot axis  135 ″. 
     As gimbal members  132 ,  138  pivot about axis  135 ″, sleeve member  140  is driven to reciprocally pivot about axis  143 ′ relative to pivoting arm  144  due to the engagement between sleeve  142  and shaft  139   b , at second connection  149 . In addition, the pivoting of gimbal member  132 ,  138  about pivot axis  135 ″ also causes pivoting arm  144  to pivot relative to carriage  150  about pivot axis  143 ″, at first connection  148 . As best shown in the sequence between  FIGS. 4 and 5 , the reciprocal pivoting of gimbal members  132 ,  138  about axis  135 ″ and the simultaneous reciprocal pivoting of sleeve member  140  and pivoting arm  144  about connections  149 ,  148  ultimately causes a reciprocal translation of second end  144   b  of pivoting arm  144  along a direction  151  that is parallel to and radially offset from axis  115 . This axial translation of second end  144   b  of pivoting arm  144  along direction  151  also causes or drives reciprocation of carriage  150  along track  156  mounted to base  103  in the direction  151 . Because carriage  150  is coupled to the piston  64  (which is disposed within fluid end  60 —see  FIG. 1 ), the reciprocation of carriage  150  along direction  151  drives the reciprocation of piston  64  within the fluid end  60  to provide a flow of pressurized working fluid from pump assembly  100  as previously described above. 
     Referring now to  FIGS. 6 and 7 , another embodiment of linking assembly (which is identified as linking assembly  230  herein) is shown for use within pump assembly  100  in place of linking assembly  130 . Many components of linking assembly  230  are the same as those found in linking assembly  130 , and thus, like components are identified with like reference numerals and the description below will focus on the components of linking assembly  230  that are different from linking assembly  130  (see  FIG. 3 ). 
     In particular, linking assembly  230  includes a spherical connection assembly  232  in place of U-Joint  121 . Spherical connection assembly  232  is mounted to second end  128   b  of offset shaft  128  and is pivotably coupled to carriage  150  via the pivoting arm assembly  141  in substantially the same manner as linking assembly  130 . Spherical connection  232  includes a clamp assembly  234  and a spherical member or ball  236 . Ball  236  includes a pair of shafts  237   a ,  237   b  that extend out of opposing sides of ball  236  along an axis  235 ″. 
     Clamp assembly  234  includes a pair of clamp members  234   a ,  234   b  that are secured to one another about ball  236  via plurality of bolts (not shown) extending through aligned apertures  237  in clamp members  234   a ,  234   b . In addition, second end  128   b  of shaft  128  is engaged with or coupled to clamp members  234   a ,  234   b  such that a projection of axis  129  is orthogonal to axis  235 ″. Further, a shaft  239  is mounted to clamp members  234   a ,  234   b  and extends along a pivot axis  235 ′. A projection of pivot axis  235 ′ is orthogonal to axis  235 ″ and is orthogonal to a projection of axis  129  of shaft  128 . Accordingly, axis  235 ″ and a projection of each of the axes  235 ′ and  129  extend through the center of ball  236 . During operations, the clamp members  234   a ,  234   b  may slidingly engage with outer surface of ball  236  such that clamp members  234   a ,  234   b  may pivot omni-directionally about ball  236  (specifically the center of ball  236 ). 
     Referring still to  FIGS. 6 and 7 , shaft  239  is received with sleeve  142  of sleeve member  140  in the same manner that shaft  139   b  is received within sleeve  142  of linking assembly  130 . In addition, shafts  237   a ,  237   b  are received within shaft mounts  145  supported on base  101  such that ball  236  is fixed relative to base  103 . Specifically, ball  236  is not configured to rotate relative to base  101  about shafts  237   a ,  237   b . As with linking assembly  130 , in  FIG. 6  only one of the shaft mounts  145  (and the associated support on base  103 ) is shown so as to better show the details of linking assembly  230 . In other examples, ball  236  may pivot relative to base  101  about shafts  237   a ,  237   b . Without being limited to this or any other theory, the rotation of ball  236  about shafts  237   a ,  237   b  may reduce some of the relative movement between ball  236  and clamp members  234   a ,  234   b  and thereby reduce wear, over time, to ball  236 . 
     Further, the same relationships exist between axes  143 ′,  143 ″ and axis  115  as described above in the embodiment of  FIGS. 2-6 . In this embodiment, axes  143 ′,  143 ″ are parallel to and radially offset from axis  235 ″, and axes  235 ″,  143 ′,  143 ″ each lie within vertically oriented planes that extend perpendicularly to a vertically oriented plane containing axis  115  of output shaft  118 . Thus, axes  235 ″,  143 ′,  143 ″ each extend in directions that are perpendicular to the direction of axis  115 . 
     During operations, as shaft  128  is orbited about axis  115  in the manner described above, clamp assembly  234  (including clamp members  234   a ,  234   b ) pivots about ball  236 . Simultaneously, shaft  239  is driven to rotate along with sleeve member  140  about axis  143 ′ relative to pivoting arm  144 , and pivoting arm  144  is pivoted about each of the axes  143 ′,  143 ″ relative to sleeve member  140  and carriage  150  in the same manner as previously described above for linking assembly  130 . As a result, carriage  150  and piston  64  are driven to reciprocate in direction  151  (e.g., along track  156 ) as previously described. 
     During the operational life of a pump assembly  100  (see  FIG. 2 ) utilizing linking assembly  230 , the sliding engagement between ball  236  and clamp members  234   a ,  234   b  may cause gradual wear of ball  236 . Due to the omni-directional movement of clamp members  234   a ,  234   b  about ball  236 , the wear may be relatively uniform so that the diameter of ball  236  will gradually decrease. In order to maintain appropriate and desired engagement between ball  236  and clamp members  234   a ,  234   b , the bolts extending through the aligned apertures  237  on clamp members  234   a ,  234   b  may be engaged or adjusted as a part of the regular maintenance of pump assembly  100  (see  FIG. 2 ). In addition, in some embodiments, one or more spacers or shims may be disposed between clamp members  234   a ,  234   b , and as ball  236  wears (and therefore shrinks) as previously described, the shims may be replaced and/or removed to provide an appropriate spacing and engagement between the clamp members  234   a ,  234   b . As a result, through use of the linking assembly  230  (which includes spherical connection assembly  232 ), the operational life of the original parts making up the linking assembly  230  may be increased (e.g., particularly ball  236 ), which thereby reduces the overall lifetime operational costs for pump assembly  100 . 
     While exemplary embodiments have been shown and described, modifications thereof can be made by one skilled in the art without departing from the scope or teachings herein. The embodiments described herein are exemplary only and are not limiting. Many variations and modifications of the systems, apparatus, and processes described herein are possible and are within the scope of the disclosure. Accordingly, the scope of protection is not limited to the embodiments described herein, but is only limited by the claims that follow, the scope of which shall include all equivalents of the subject matter of the claims. Unless expressly stated otherwise, the steps in a method claim may be performed in any order. The recitation of identifiers such as (a), (b), (c) or (1), (2), (3) before steps in a method claim are not intended to and do not specify a particular order to the steps, but rather are used to simplify subsequent reference to such steps.