Patent Publication Number: US-10757857-B2

Title: Meter roller insert system

Description:
BACKGROUND 
     The disclosure relates generally to a meter roller for an agricultural metering system. 
     Generally, seeding implements (e.g., seeders) are towed behind a tractor or other work vehicle via a mounting bracket secured to a rigid frame of the implement. Seeding implements typically include multiple row units distributed across a width of the implement. Each row unit is configured to deposit seeds at a target depth beneath the soil surface of a field, thereby establishing rows of planted seeds. For example, each row unit typically includes a ground engaging tool or opener that forms a seeding path (e.g., trench) for seed deposition into the soil. A seed tube (e.g., coupled to the opener) is configured to deposit seeds and/or other agricultural products (e.g., fertilizer) into the trench. The opener/seed tube may be followed by closing discs that move displaced soil back into the trench and/or a packer wheel that packs the soil on top of the deposited seeds. 
     In certain configurations, an air cart is used to meter and deliver agricultural product (e.g., seeds, fertilizer, etc.) to the row units of the seeding implement. The air cart generally includes a storage tank (e.g., a pressurized tank), an air source (e.g., a blower), and a metering system. The product is typically gravity fed from the storage tank to the metering system which distributes a desired volume of product into an air flow generated by the air source. The air flow carries the product to the row units via conduits extending between the air cart and the seeding implement. The metering system typically includes meter rollers that regulate the flow of product based on meter roller geometry and rotation rate. 
     BRIEF DESCRIPTION 
     In one embodiment, a modular meter roller for an agricultural metering system. The modular meter roller includes a first roller segment that couples to and rotates with a shaft to meter flowable particulate material. The first roller segment includes a body that defines an aperture. The aperture receives the shaft and the aperture defines a plurality of vertices. A first plurality of fins extending radially outward from the body. The first plurality of fins defines a first plurality of grooves in the first roller segment that receives flowable particulate material. A vertex of the plurality of vertices of the aperture is offset from a longitudinal axis of a fin of the first plurality of fins. 
     In another embodiment, a modular meter roller for an agricultural metering system. The modular meter roller includes first roller segment that couples to and rotates with a shaft to meter flowable particulate material. The first roller segment includes a body defining an aperture. The aperture receives the shaft and the aperture defines a plurality of vertices. A first plurality of flutes in the body that defines a plurality of grooves in the first roller segment that receives flowable particulate material. A vertex of the plurality of vertices of the aperture is offset from a longitudinal axis of a flute tip of the first plurality of flutes. 
     In another embodiment, a modular meter roller for an agricultural metering system. The modular meter roller includes a first roller segment that couples to and rotates with a shaft to meter flowable particulate material. The first roller segment includes a first body that defines a first aperture. The first aperture receives the shaft and the first aperture defines a first plurality of vertices. A first plurality of fins or flutes with a first vertex of the first plurality of vertices of the first aperture is offset from a longitudinal axis of a first fin or first flute tip of the first plurality of fins or flute tips. A first alignment feature aligns the first roller segment with a second roller segment to stagger the first plurality of fins or flutes with a second plurality of fins or flutes on the second roller segment. 
    
    
     
       DRAWINGS 
       These and other features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein: 
         FIG. 1  is a side view of an air cart, including a metering system configured to regulate a flow of particulate material, according to an embodiment of the disclosure; 
         FIG. 2  is a schematic view of a metering system that may be employed within the air cart of  FIG. 1 , according to an embodiment of the disclosure; 
         FIG. 3  is an exploded perspective view of a metering system that may be employed within the air cart of  FIG. 1 , according to an embodiment of the disclosure; 
         FIG. 4  is a perspective view of the metering system of  FIG. 3 , in which a cartridge is disposed within a meter box, according to an embodiment of the disclosure; 
         FIG. 5  is a cross-sectional view of the metering system of  FIG. 3 , according to an embodiment of the disclosure; 
         FIG. 6  is a perspective view of the metering system of  FIG. 3 , in which the cartridge is removed from the meter box, according to an embodiment of the disclosure; 
         FIG. 7  is an exploded perspective view of the cartridge of  FIG. 4 , in which a modular meter roller is removed from a housing of the cartridge, according to an embodiment of the disclosure; 
         FIG. 8  is a top view of the cartridge of  FIG. 4 , according to an embodiment of the disclosure; 
         FIG. 9  is an exploded perspective view of a modular meter roller, according to an embodiment of the disclosure; 
         FIG. 10  is a perspective view of the assembled modular meter roller of  FIG. 9 , according to an embodiment of the disclosure; 
         FIG. 11  is a perspective view of an assembled modular meter roller, according to an embodiment of the disclosure; 
         FIG. 12  is a side view of a shaft of the modular meter roller of  FIG. 9 , according to an embodiment of the disclosure; 
         FIG. 13  is an end view of the shaft of the modular meter roller of  FIG. 9 , according to an embodiment of the disclosure; 
         FIG. 14  is an end view of a roller segment, according to an embodiment of the disclosure; 
         FIG. 15  is an end view of two superimposed roller segments, according to an embodiment of the disclosure; 
         FIG. 16  is an end view of a roller segment, according to an embodiment of the disclosure; 
         FIG. 17  is an end view of a roller segment, according to an embodiment of the disclosure; 
         FIG. 18  is an end view of a roller segment, according to an embodiment of the disclosure; 
         FIG. 19  is a partial end view of a roller segment, according to an embodiment of the disclosure; 
         FIG. 20  is an exploded perspective view of a modular meter roller, according to an embodiment of the disclosure; 
         FIG. 21  is an exploded perspective view of a modular meter roller, according to an embodiment of the disclosure; 
         FIG. 22  is an exploded perspective view of a modular meter roller, according to an embodiment of the disclosure; and 
         FIG. 23  is an exploded perspective view of a modular meter roller, according to an embodiment of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Turning now to the drawings,  FIG. 1  is a side view of an air cart  10  that may be used in conjunction with a towable agricultural implement to deposit seeds into soil. For example, certain agricultural implements include row units configured to open the soil, dispense seeds into the soil opening, and re-close the soil. Such implements are generally coupled to a tow vehicle, such as a tractor, and pulled through a field. In certain configurations, seeds are conveyed to the row units by the illustrated air cart  10 , which is generally towed in sequence with the implement along a direction of travel  11  (e.g., behind the implement or in front of the implement). In certain configurations, the air cart  10  may be configured to provide fertilizer to the row units, or a combination of seeds and fertilizer. 
     In the illustrated embodiment, the air cart  10  includes a storage tank  12 , a frame  14 , wheels  16 , a metering system  18 , and an air source  20 . In certain configurations, the storage tank  12  includes multiple compartments for storing various flowable particulate materials. For example, one compartment may include seeds, such as canola or mustard, and another compartment may include a dry fertilizer. In such configurations, the air cart  10  is configured to deliver both the seeds and fertilizer to the implement. The frame  14  includes a towing hitch configured to couple to the implement or tow vehicle. As discussed in detail below, seeds and/or fertilizer within the storage tank  12  are gravity fed into the metering system  18 . The metering system  18  includes one or more meter rollers that regulate the flow of material from the storage tank  12  into an air flow provided by the air source  20 . The air flow then carries the material to the implement by pneumatic conduits. In this manner, the row units receive a supply of seeds and/or fertilizer for deposition within the soil. 
       FIG. 2  is a schematic view of the metering system  18 , as shown in  FIG. 1 . As illustrated, the air source  20  is coupled to a conduit  22  configured to flow air  24  past the metering system  18 . The air source  20  may be a pump or blower powered by an electric or hydraulic motor, for example. Flowable particulate material  26  (e.g., seeds, fertilizer, etc.) within the storage tank  12  flows by gravity into the metering system  18 . In certain embodiments, the storage tank  12  is pressurized such that a static pressure in the tank  12  is greater than a static pressure in the conduit  22 , thereby facilitating an even flow of material through the metering system  18 . The metering system  18  includes one or more modular meter rollers  28  configured to regulate the flow of material  26  into the air flow  24 . In certain embodiments, the metering system  18  may include multiple modular meter rollers  28  (e.g., housed within individual meter boxes) disposed adjacent to one another. In addition, certain metering systems  18  may include twelve modular meter rollers  28 , each housed within an individual meter box and each configured to flow particulate material into a respective conduit  22  (e.g., of a material distribution system) for distribution to one or more respective row units of the agricultural implement. However, in alternative embodiments, the metering system  18  may include more or fewer meter rollers, e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, or more. By independently adjusting the rotation speed of each meter roller, product flow to different portions of the implement may be particularly controlled. 
     In the illustrated embodiment, the modular meter roller  28  is coupled to a drive assembly  30  configured to drive the modular meter roller  28  to rotate. In certain embodiments, the drive assembly  30  includes at least one drive unit, such as an electric or hydraulic motor, configured to drive one or more meter rollers to rotate. For example, in certain embodiments, multiple drive units may be coupled to respective meter rollers to facilitate independent control of the rotation rates of the meter rollers. In further embodiments, the drive assembly  30  may be coupled to a wheel (e.g., via a gear assembly) such that rotation of the wheel drives the modular meter roller  28  to rotate. Such a configuration automatically varies the rotation rate of the modular meter roller  28  based on the speed of the air cart. 
     The modular meter roller  28  also includes protrusions, such as the illustrated fins  32 , and recesses  34 . Each respective recess  34  is disposed between a respective pair of fins  32 . As the modular meter roller  28  rotates, the respective pair of fins  32  moves the material  26  (e.g., agricultural product) disposed within the respective recess  34  downwardly, thereby transferring the material  26  to the conduit  22 . The number and geometry of the fins  32  are particularly configured to accommodate the material  26  being distributed. Certain modular meter rollers  28  may include six fins  32  and a corresponding number of recesses  34 . Alternative meter rollers may include more or fewer fins  32  and/or recesses  34 . For example, the modular meter roller  28  may include 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, or more fins  32  and/or recesses  34 . In addition, the depth of the recesses  34  and/or the height of the fins  32  are configured to accommodate the material  26  within the storage tank  12 . For example, a meter roller having deeper recesses  34  and fewer fins  32  may be employed for larger seeds, while a meter roller having shallower recesses  34  and more fins  32  may be employed for smaller seeds. Other parameters such as fin pitch (i.e., angle of the fin relative to a longitudinal/rotational axis) and fin angle (i.e., angle of the fin relative to a radial axis) may also be particularly selected to accommodate the material  26 . While the illustrated meter roller includes fins, it should be appreciated that in alternative embodiments, the meter roller may include other protrusions, and/or the recesses may be omitted. 
     In the illustrated embodiment, the rotationally axis of the modular meter roller  28  is oriented substantially parallel to the direction of travel  11  of the air cart. As used herein, substantially parallel may refer to an angle of about 0 to about 45 degrees, about 0 to about 30 degrees, about 0 to about 15 degrees, about 0 to about 5 degrees, or about 0 to about 1 degree relative to an axis/direction (e.g., the direction of travel  11 ). By way of example, substantially parallel may refer to an angle less than 5 degrees, less than 4 degrees, less than 3 degrees, less than 2 degrees, less than 1 degree, or less than 0.5 degrees relative to an axis/direction. In further embodiments, the meter roller may be oriented substantially perpendicular to the direction of travel, or at any other suitable angle. 
     For a particular meter roller configuration/profile, the rotation rate of the modular meter roller  28  controls the flow of material  26  into the air flow  24 . For example, as the modular meter roller  28  rotates, the meter roller transfers material through an opening  36  in the metering system  18  into a respective conduit  22  (e.g., into a conduit associated with a respective row unit or group of row units). The material then mixes with air from the air source  20 , thereby forming an air/material mixture  38 . The mixture then flows to the respective row unit(s) of the implement via pneumatic conduit(s), where the seeds and/or fertilizer are deposited within the soil. 
     Different flowable particulate materials may include particles of different sizes. For example, seeds, such as sunflower, may have a coarse particle size, fertilizer, such as monoammonium phosphate (MAP), may have a medium particle size, and inoculant, such as a granular microbial soil inoculant, may have a fine particle size. Moreover, the target application rate may vary based on the type of flowable particulate material being dispensed. For example, the target flow rate of certain seeds or fertilizers may be higher than the target flow rate of other seeds or fertilizers. Accordingly, certain embodiments of the metering system disclosed herein may facilitate removal and replacement of meter rollers, thereby enabling an operator to select a meter roller suitable for a particular flowable particulate material and for a target dispensing rate (e.g., a target rate for particular field conditions, climate, expected yield, etc.). 
       FIG. 3  is an exploded perspective view of an embodiment of a metering system  18  that may be employed within the air cart of  FIG. 1 . The metering system  18  includes a meter box  40  and a drive assembly  30 . The meter box  40  has a passage  42  configured to direct the flowable particulate material to the conduit  22  for transfer to a row unit or group of row units. As shown in  FIG. 3 , the meter box  40  has a first side  43  (e.g., drive side) for receiving a drive unit  46  of the drive assembly  30 . In the illustrated embodiment, the drive unit  46  includes a drive shaft  44  and a motor (e.g., electric motor)  45  that drives the drive shaft to rotate in a clockwise or counter-clockwise direction. The drive unit  46  and the meter box  40  include apertures  50  configured to receive fasteners (e.g., bolts)  52  to secure the drive unit  46  to the meter box  40 . The drive shaft  44  is inserted into an opening  54  in the meter box such that the drive shaft  44  engages the meter roller within the meter box  40 . The drive shaft  44  is configured to drive the meter roller to rotate. A bearing (e.g., ball bearing)  56  facilitates rotation of the drive shaft  44  and meter roller within the meter box  40 . As the conduit  22  transfers air under the passage  42 , the motor (e.g., electric motor) of the drive unit  46  drives the drive shaft  44  to rotate the meter roller. As the meter roller rotates, the meter roller dispenses flowable particulate material via the passage  42  to the air flow within the conduit  22  to form the air/material mixture. Further, pressurized air from the tank may flow through the passage  42  with the material from the meter roller. 
     In the illustrated embodiment, the drive shaft  44  includes a first engagement feature  58 , such as protrusions, configured to non-rotatably couple the drive shaft  44  to the meter roller. The protrusions may engage corresponding recesses of the meter roller, thereby non-rotatably coupling the drive shaft  44  to the meter roller. While the drive unit  46  includes an electric motor in the illustrated embodiment, it should be appreciated that in alternative embodiments, the drive unit may include any other suitable system configured to drive rotation of the meter roller, such as a hydraulic motor, a pneumatic motor, or a gear assembly coupled to a wheel of the air cart. 
       FIG. 4  is a perspective view of the metering system  18  of  FIG. 3 , in which a cartridge  60  is disposed within the meter box  40 . As discussed in detail below, the cartridge  60  (e.g., modular meter roller cartridge) is configured to facilitate removal and installation of the meter roller via a meter box opening on a second side  61  (e.g., cartridge side) of the meter box  40 . As illustrated, the meter box  40  houses the cartridge  60  while the cartridge is disposed within the opening. While the cartridge  60  is housed within the meter box  40  of the metering system  18  in the illustrated embodiment, it should be appreciated that in alternative embodiments, the meter box may house a meter roller without a cartridge, or the meter box may house multiple cartridges (e.g., 2, 3, 4, 5, 6, or more). 
     In the illustrated embodiment, the metering system  18  is configured to enable the cartridge  60  to engage the meter box  40  via the meter box opening in the second side  61  (e.g., cartridge side) of the meter box  40 . While the cartridge  60  is engaged with the meter box  40 , the shaft of the drive unit engages the meter roller, thereby enabling the meter roller to be driven in rotation. The cartridge  60  has a cross-sectional shape that substantially corresponds to the cross-sectional shape of the meter box opening. As illustrated, the meter box  40  includes two cartridge locking tabs  62  configured to selectively block removal of the cartridge  60  from the meter box  40 , thereby retaining the cartridge  60  within the meter box  40 . In the illustrated embodiment, each locking tab  62  is part of a rotatable latch configured to rotate between the illustrated locked position that blocks removal of the cartridge  60  from the meter box  40  and an unlocked position that facilitates removal of the cartridge  60  from the meter box  40 . In certain embodiments, each cartridge locking tab includes a recess that engages a corresponding notch on the cartridge  60  to block unintentional rotation of the rotatable latch while the rotatable latch is in the locked position (e.g., due to vibrations of the air cart). The cartridge  60  may be removed by rotating each rotatable latch in a respective first direction and extracting the cartridge  60 . Further, the cartridge  60  may be inserted by engaging the cartridge with the meter box  40 , and then rotating each latch in a respective second direction, opposite the respective first direction. While each cartridge locking tab  62  is part of a rotatable latch in the illustrated embodiment, it should be appreciated that in alternative embodiments, the cartridge locking tab may be part of a spring latch, a bolt latch, or any suitable type of locking mechanism. Furthermore, while the illustrated meter box includes two locking tabs, it should be appreciated that in alternative embodiments, the meter box may include more or fewer locking tabs (e.g., 1, 2, 3, 4, etc.). In the illustrated embodiment, the cartridge  60  includes a releasable bearing coupler  68 . As discussed in detail below, the releasable bearing coupler  68  retains the meter roller within the cartridge, facilitates rotation of the meter roller within the cartridge, and facilitates removal of the meter roller from the cartridge. 
       FIG. 5  is a cross-sectional view of the metering system  18  of  FIG. 3 . As illustrated, the cartridge  60  is engaged with/disposed within the meter box  40  of the metering system  18 . The cartridge  60  includes a housing  70  configured to rotatably support the modular meter roller  28  within the meter box  40  (e.g., the housing  70  is secured to the meter box while the modular meter roller  28  rotates). The housing  70  includes a first side  72  (e.g., cartridge drive side) and a second side  74  (e.g., cartridge bearing side), which correspond to the first side  43  and second side  61  of the meter box  40 , respectively. 
     The cartridge  60  includes a bearing opening  76  for receiving the releasable bearing coupler  68 , and in certain embodiments, a meter roller bearing  78 , which may engage the modular meter roller  28 . The modular meter roller  28  includes a driven shaft  80  configured to engage the drive shaft of the drive unit, thereby non-rotatably coupling the drive shaft to the meter roller. The driven shaft  80  includes a second engagement feature  84  (e.g., recesses) configured to selectively engage the first engagement feature (e.g., protrusions) of the drive shaft. The driven shaft may be an integral part of a meter roller spindle, and the fins and recesses of the meter roller may be formed on one or more meter roller inserts non-rotatably coupled to the spindle. While the second engagement feature includes recesses in the illustrated embodiment, it should be appreciated that in alternative embodiments, the second engagement feature may include a cavity having a polygonal cross-section and configured to engage the drive shaft having a corresponding polygonal cross-section (e.g., first engagement feature). Furthermore, while the illustrated second engagement feature  84  facilities shape-based engagement with the first engagement feature, it should be appreciated that in alternative embodiments, any variety of suitable interlocking mechanisms may be utilized for non-rotatably coupling the meter roller to the drive shaft. 
     In the illustrated embodiment, a drive bearing  86  is used to facilitate rotation of the drive shaft within the meter box. The drive bearing  86 , the driven shaft  80 , the drive shaft, and the meter roller bearing  78  associated with the releasable bearing coupler  68  are in longitudinal alignment, thereby facilitating rotation of the modular meter roller  28  in response to rotation of the drive shaft. The meter roller bearing  78  may be coupled to the releasable bearing coupler  68 , the driven shaft  80 , or it may be a separate individual element. While the cartridge  60  is engaged with/disposed within the meter box  40 , the housing  70  rotatably supports/houses the modular meter roller  28 . To change a modular meter roller  28 , the operator may remove the cartridge  60 , replace the modular meter roller  28 , and then reinstall the cartridge  60 . Alternatively, the operator may remove the cartridge  60  and replace the cartridge with another cartridge that contains a different meter roller or with a different cartridge type. 
       FIG. 6  is a perspective view of the metering system of  FIG. 3 , in which the cartridge  60  is removed from the meter box  40 . To remove the cartridge  60 , the operator may rotate the rotatable latches to the unlocked position, in which the locking tabs  62  are positioned to facilitate removal of the cartridge, and extract the cartridge  60  from the meter box  40 . As illustrated, the cross-sectional shape of the cartridge  60  (e.g., the cross-sectional shape of the first side  72 , the cross-sectional shape of the second side  74 , etc.) substantially correspond to the cross-sectional shape of the meter box opening  88 . 
     As illustrated, the modular meter roller  28  includes fins  32  and recesses  34 , which are configured to enable the modular meter roller  28  to control the flow of the flowable particulate material into the passage  42 . The modular meter roller  28  is rotatably supported on the second side  74  of the meter roller cartridge  60  by the releasable bearing coupler  68 . Once the cartridge  60  is removed from the meter box  40 , the releasable bearing coupler  68  may be disengaged and removed from the meter roller/housing. Once the rotatable bearing coupler  68  is removed, the modular meter roller  28  may be removed through an opening  90 , thereby enabling insertion of another meter roller (e.g., suitable for use with material having a larger or small particle size, and/or for a higher or lower target application rate). 
       FIG. 7  is an exploded perspective view of the cartridge  60  of  FIG. 4 , in which the modular meter roller  28  is removed from the housing  70  of the cartridge  60 . The housing  70  of the cartridge  60  has a drive shaft opening  92  on the first side  72  of the housing  70  and the bearing opening  76  on the second side  74  of the housing  70 . The housing  70  also has the meter roller opening  90  and material receiving openings  94 . The material receiving openings  94  are configured to receive the flowable particulate material into the housing  70 , thereby enabling the modular meter roller  28  to receive the material. 
     To couple the modular meter roller  28  to the housing  70 , the modular meter roller  28  is disposed within the housing  70  through the meter roller opening  90 . While the modular meter roller  28  is disposed within the housing  70 , the drive shaft opening  92  on the first side  72  of the housing  70  aligns with the drive shaft opening (e.g., a recess or interior cavity) of the driven shaft. In addition, the bearing opening  76  on the second side  74  of the housing  70  aligns with a bearing opening  96  (e.g., a recess or interior cavity) of the modular meter roller  28 . The bearing opening  96  may be configured to receive the bearing  78  or the bearing may be fixedly mounted within the opening  96 . The openings of the modular meter roller  28  and cartridge  60  are longitudinally aligned with one another and with the drive shaft. 
     The meter roller cartridge  60  and/or the releasable bearing coupler  68  may include gaskets  100 . While two gaskets  100  (e.g., O-rings) are included in the illustrated embodiment, it should be appreciated that in alternative embodiments, any suitable number of gaskets (e.g., O-rings) may be used to seal adjacent parts. Once the modular meter roller  28  is disposed within the housing  70 , the bearing opening  96  may receive the releasable bearing coupler  68 , and in certain embodiments the meter roller bearing  78 , via the bearing opening  76  in the housing  70 . The meter roller bearing  78  may be fixedly coupled to the modular meter roller  28  or fixedly coupled to the releasable bearing coupler  68  in certain embodiments. In further embodiments, the meter roller bearing  78  may be an independent element. The releasable bearing coupler  68  may include the bearing  78 , or the releasable bearing coupler  68  may be configured to engage the bearing  78  with a shaft of the releasable bearing coupler  68 . Accordingly, the bearing  78  may be configured to engage the opening  96  of the modular meter roller  28  to facilitate rotation of the modular meter roller  28  relative to the housing  70  (e.g., rotation about the shaft of the releasable bearing coupler). The bearing coupler  68  is configured to engage the bearing opening  76  and to couple to the housing  70  via corresponding locking elements of the bearing coupler  68  and the housing  70 . For example, the locking elements may interlock with one another via rotation of the bearing coupler  68  relative to the housing, thereby coupling the bearing coupler  68  to the housing  70 . While the bearing coupler  68  is coupled to the housing  70 , the shaft of the bearing coupler  68  rotatably supports the modular meter roller  28  and secures the meter roller to the housing  70 . 
       FIG. 8  is a top view of the cartridge  60  of  FIG. 4 . In the illustrated embodiment, the modular meter roller  28  within the cartridge  60  is configured to meter flowable particulate material having fine particles at a low rate. Accordingly, the aggregate volume of the recesses may be less than a meter roller configured to meter larger particles at a faster rate. In the illustrated embodiment, the circumferential extent of each fin  32  (e.g., extent of each fin  32  along a circumferential axis  102 ) is at least 1.5 times greater than the circumferential extent of each recess  34  (e.g., extent of each recess  34  along the circumferential axis  102 ) along an entire longitudinal extent  104  or  105  of the fin  32  and the recess  34  (e.g., the entire extent  104  of the fin  32  and the recess  34  of a first rank  132  along a longitudinal axis  106 , and an entire extent  105  of the fins  32  and the recesses  34  of a second rank  134  along the longitudinal axis  106 ). Furthermore, the entire longitudinal extent  104  or  105  of each fin  32  and each recess  34  is greater than the circumferential extent of the fin and the circumferential extent of the recess. 
     In the illustrated embodiment, the longitudinal extent  104  of the fins  32  and recesses  34  of the first rank  132  is substantially equal to a width  108  of a respective material receiving opening  94  (e.g., extent of the material receiving opening  94  along the longitudinal axis  106 ). In addition, the longitudinal extent  105  of the fins  32  and recesses  34  of the second rank  134  is substantially equal to a width  109  of a respective material receiving opening  94  (e.g., extent of the material receiving opening  94  along the longitudinal axis  106 ). For example, the fin/recess longitudinal extent  104 ,  105  and the opening width  108 ,  109  may be between about 20 and about 75 mm, about 30 and about 50 mm, about 47.5 mm, or about 32.5 mm. As previously discussed, the flowable particulate material flows through the material receiving openings  94  to the modular meter roller  28 . The width  108 ,  109  of the material receiving openings substantially reduces or eliminates the possibility of the openings becoming blocked due to clumping of the flowable agricultural product (e.g., as compared to a narrower opening, such as the auxiliary opening  110 , which is currently blocked). However, the wider openings enable more flowable particulate material to flow to the meter roller. Accordingly, the illustrated modular meter roller  28  includes recesses  34  that have a small aggregate volume to establish a low flow rate for a particular meter roller rotation speed. For example, as previously discussed, the recesses are circumferentially spaced apart from one another by more than 1.5 times the circumferential extent of the recesses. In addition, the depth of each recess (e.g., extent of the recess along a radial axis  112 ) is shallow to reduce the aggregate volume of the recesses. As a result of the meter roller configuration, the meter roller may provide flowable particulate material to the distribution system at a low flow rate while substantially reducing or eliminating the possibility of blocking the material receiving openings with clumped material. 
     Meter rollers may be characterized by a ratio of aggregate recess volume to width of the material receiving opening. In the illustrated embodiment, each recess  34  of the first rank  132  has a volume of about 183 mm 3 , and each rank (e.g., the first rank  132  and the second rank  134 ) has nine recesses. Accordingly, the aggregate recess volume for the first rank  132  is about 1643 mm 3 . As previously discussed, the width  108  of the respective material receiving opening  94  (e.g., the opening  94  configured to provide flowable particulate material to the first rank  132 ) is about 47.5 mm. Accordingly, the ratio of aggregate recess volume to opening width for the first rank  132  is about 34. However, it should be appreciated that in certain embodiments, the ratio may be higher or lower (e.g., depending on the number of recesses and the volume of each recess). For example, to establish a low flow rate of fine particulate material while substantially reducing or eliminating the possibility of blocking the material receiving openings, the ratio may be less than about 50, less than about 45, less than about 40, less than about 35, or less than about 30. Utilizing such a meter roller profile may enable the motor of the drive unit to rotate the meter roller at a speed sufficient to facilitate precise control of the meter roller rotation rate (e.g., as compared to rotating a meter roller having a larger aggregate recess volume slower than a minimum controllable speed of the motor). 
     In the illustrated embodiment, the longitudinal axis  114  of each fin  32  is substantially parallel to the rotational axis  116  of the modular meter roller  28 . In addition, the longitudinal axis  118  of each recess  34  is substantially parallel to the rotational axis  116  of the modular meter roller  28 . However, as discussed in detail below, in alternative embodiments, the longitudinal axis of each fin and the longitudinal axis of each recess may be oriented at an angle (e.g., of at least 2 degrees) relative to the rotational axis of the meter roller. Furthermore, in certain embodiments, the fins and recesses may follow a curved path from one longitudinal side of a rank to the other longitudinal side of the rank. 
     In the illustrated embodiment, the modular meter roller  28  is formed from a spindle  120  and profile inserts  122 . As discussed in detail below, the profile inserts, which form the fins and recesses of the meter roller, are arranged in ranks, and the profile inserts of each rank are coupled to one another and non-rotatably coupled to the spindle. Accordingly, as the drive shaft drives the spindle  120 , which includes the driven shaft, to rotate, the profile inserts  122  are driven to rotate, thereby inducing the fins and the recesses to meter the flowable particulate material to the distribution system. In the illustrated embodiment, the spindle  120  includes a first ring  124 , a second ring  126 , a third ring  128 , and a fourth ring  130 . Each ring is rigidly and non-rotatably coupled to (e.g., integrally formed with) the driven shaft. A first rank  132  of profile inserts  122  is longitudinally disposed between the first ring  124  and the second ring  126 , and a second rank  134  of profile inserts  122  is longitudinal disposed between the second ring  126  and the third ring  128 . In addition, a sealing ring  136  is longitudinally disposed between the third ring  128  and the fourth ring  130 . As discussed in detail below, the sealing ring  136  is configured to block the flowable particulate material from entering an interior of the spindle  120 . 
       FIG. 9  is an exploded perspective view of a modular meter roller  28 . The modular meter roller  28  enables a user to swap/replace roller segments  160  to accommodate metering of different types of product (e.g., seed, fertilizer). For example, some seeds may be large than others, such as corn versus canola. In order to meter differently sized seeds and/or other products at a desired rate, the modular meter roller  28  may change the roller segments  160 . As will be explained below, the roller segments  160  may differ in the number of fins  162 , size of grooves  164 , depth of the grooves  164 , as well as the profile of the fins  162  and/or the grooves  164  in order to accommodate different types of metered products. 
     The illustrated modular meter roller  28  includes three separate roller segments  160  that are configured to couple to the shaft  166 . In other embodiments, the modular meter roller  28  may include a different number of roller segments  160  (e.g., one, two, three, four, five, six). Each of these roller segments  160  may differ from the other roller segments  160  in its number of fins  162 , size of the grooves  164 , profile, and/or a combination thereof. In this way, the modular meter roller  28  may enable metering of different products simultaneously through the metering system  18 . The different roller segments  160  may also enable metering of different products at different times without removing and changing the modular meter roller  28 . That is, some of the roller segments  160  on the modular meter roller  28  may meter a particular product while other roller segments  160  on the same modular meter roller  28  meter a different product. As will be explained below, in some embodiments the fins  162  and grooves  164  of the roller segments  160  may be offset (e.g., radially offset) from one another about the shaft  166 . In operation, the offset between the roller segments  160  may reduce and/or block pulsing (e.g., vibration) of the modular meter roller  28  and thus vibration of the meter system  18 . 
     In some embodiments, the shaft  166  may include multiple sections that accommodate different apertures of the roller segments  160 . For example, the shaft  166  may include a first section  168  that defines a first diameter  170  and a second shaft section  172  that defines a second diameter  174 . These shaft sections  168  and  172  may have a specific cross-sectional shape that enables the shaft  166  to couple to the roller segments  160  and to transfer force from the motor to the roller segments  160 . For example, the first shaft section  168  may define a dodecahedron exterior surface profile, while the second shaft section  172  may define a hexagon exterior surface profile. These exterior surface profiles correspond to the profile of the apertures  175  in the roller segments  160  enabling the roller segments  160  to couple to and rotate with the shaft  166 . 
     As illustrated, a first end plate  176  couples to the first section  168  of the shaft  166 . The first end plate  176  is configured to block removal of the roller segments  160  in direction  178 . The roller segments  160  are separated by discs  180  that couple to the shaft  166 . The discs  180  may reduce and/or block metered product from moving between the roller segments  160 . In order to block the flow of product between the roller segments  160 , the discs  180  define a diameter  181  that is equal to or greater than the diameter of the roller segments  160 . In some embodiments, the discs  180  may define apertures  182  that correspond to a profile of the shaft  166  (e.g., hexagon profile) enabling the shaft  166  to drive rotation of the discs  180  as well as the roller segments  160 . 
     In order to block removal of the discs  180  and the roller segments  160  from the shaft  166 , the modular meter roller  28  may include an end plate  184 . The end plate  184  couples to the second shaft section  172  with one or more fasteners  186  (e.g., threaded fasteners) that couple to an end face  188  of the shaft  166 . 
       FIG. 10  is a perspective view of the assembled modular meter roller  28  of  FIG. 9 . As illustrated, the roller segments  160  are separated from each other by the discs  180  enabling each roller segment  160  to meter product independently. Accordingly, each roller segment  160  may therefore facilitate metering of a particular product. In some embodiments, the roller segments  160  of the modular meter roller  28  may be offset from each other about the axis  190  of the shaft  166 . That is, the fins  162  and grooves  164  of the roller segments  160  may be offset (e.g., radially offset) from one another about the shaft  166 . By radially offsetting the roller segments  160 , seed and/or particulate may fill and discharge from the grooves  164  at different times as the shaft  166  rotates. Accordingly, the vibration generated by filling and discharging particulate from the roller segments  160  may not occur simultaneously along the axis  190  of the shaft  166 , which may reduce and/or block pulsing (e.g., vibration) of the modular meter roller  28  and thus vibration of the meter system  18 . 
       FIG. 11  is a perspective view of an assembled modular meter roller  28  with roller segments  160 . The modular meter roller  28  includes four separate roller segments  200 ,  202 ,  204 , and  206 . As illustrated, separation discs  180  separate the roller segments  200  and  202 , and the roller segment  202  from the roller segments  204  and  206 . As explained above, the separation discs  180  block may reduce and/or block metered product from moving between the roller segments  160 . However in some embodiments, the modular meter roller  28  may not include a disc  180  between some or all of the roller segments  160 . As illustrated, the roller segments  204  and  206  are not separated by a disc  180 . Instead, the roller segments  204  and  206  are radially offset from each other about the axis  190  of the modular meter roller  28 . This offset may enable the roller segments  202  and  204  to reduce pulsing/vibration of the modular meter roller  28  while also reducing the transfer of product between the roller segments  204  and  206 . 
       FIG. 12  is a side view of a shaft  166  of the modular meter roller of  FIG. 9 . As explained above, the shaft  166  may include multiple sections. These sections may have different shapes and diameters. The shaft  166  includes a first section  168  that defines a first diameter  170  and a second shaft section  172  that defines a second diameter  174 . These shaft sections  168  and  172  may have a specific cross-sectional shape that enables the shaft  166  to couple to the roller segments  160  and to transfer force from the motor to the roller segments  160 . For example, the first shaft section  168  may define a dodecahedron exterior surface profile, while the second shaft section  172  may define a hexagon exterior surface profile. These exterior surface profiles correspond to apertures in the roller segments  160  enabling the roller segments  160  to couple to and rotate with the shaft  166 . The length of these sections may also differ. For example, the first section  168  may define a length  220  while the second section  172  defines a second length  222 . The lengths of these sections  168  and  172  may correspond to the lengths or cumulative lengths of the roller segments  160 . While two section are illustrated, the shaft  166  may include multiple sections (e.g., 1, 2, 3, 4, 5, or more) with different diameters. Each of these sections may define the same or different exterior surface profiles (e.g., hexagon, octagon, nonagon, decagon) that matches the aperture in the roller segments  160 . As illustrated, the end plate  176  couples to the first section  168  of the shaft  166 . The first end plate  176  is configured to block removal of the roller segments  160  in direction  178 . In some embodiments, the first shaft section  168 , the second shaft section  172 , and the end plate  176  may be one-piece (e.g., integral). 
       FIG. 13  is an end view of the shaft  166  of the modular meter roller  28  of  FIG. 9 . As explained above, the shaft  166  includes the first shaft section  168 , the second shaft section  172 , and the end plate  176 . As illustrated, the shaft  166  includes an aperture  240 . The aperture  240  receives the drive shaft  44  enabling the motor  45  to drive rotation of the modular meter roller  28 . As explained above, a second plate  184  couples to the end face  188  of the second shaft section  172 . In order to couple the second plate  184  to the end face  188 , the second shaft section  172  may define one or more apertures  242 . The apertures  242  receive the fasteners  186  which couple the second plate  184  to the shaft  166 . Once coupled to the shaft  166 , the second plate  184  blocks removal of the roller segments  160  from the shaft  166 . While three apertures  242  are illustrated in  FIG. 13 , other embodiments may include a different number of apertures  242  (e.g., 1, 2, 3, 4, 5, or more). 
       FIGS. 14, 15, 16, 17, and 18  are cross-sectional views of roller segments that may be used in the modular meter roller  28  of  FIG. 9 . Each of these roller segments may differ from each other in their number of fins, size of grooves (e.g., fins), profile, and/or a combination thereof. In  FIG. 14 , the roller segment  260  includes six fins  262  equally spaced about an axis  264 . Between each of the fins  262  is a groove  266 . The grooves  266  receive the particulate as the roller segment  260  rotates about the axis  264  during operation of the modular meter roller  28 . In some embodiments, the fins  262  define curved surfaces  268  between the tips  270  and the exterior surface or base  272  of the roller segment  260 . The profile of the roller segment  260  between the fins  262  may therefore form a generally concave surface. In operation, as the roller segment  260  receives product, the curved surfaces  268  (e.g., concave profile) guide product into the grooves  266 , which may reduce or limit the impact experienced by the product (e.g., seeds) as the product fills the grooves  266 . 
     The roller segment  260  defines an aperture  272  that receives the shaft  166  enabling the roller segment  260  to couple to the modular meter roller  28 . In  FIG. 14 , the aperture  272  is in the form of a hexagon. In other embodiments, the aperture  272  may have a different shape (e.g., octogon, decagon) that corresponds to the shape of the shaft  166 . As explained above, the fins  262  are equally spaced from each other about the axis  264 . The angle  273  between each of the fins  262  is therefore sixty degrees. 
     As illustrated, the fins  262  and the aperture  272  are not aligned. That is, the vertices  274  of the hexagonal aperture  272  do not align with the axis  276  of the respective fins  262 . As illustrated, the vertices  274  of the hexagonal aperture  272  are offset from the axis  276  of the proximate fins  262  by the angle  277 . In  FIG. 14 , the vertices  274  of the hexagonal aperture  272  are offset from the axis  276  of the proximate fins  262  by half the angle  273  formed by neighboring fins  262  (i.e., 30°). This offset enables staggering (e.g., half-turn staggering) of the fins  262  of two roller segments  260  by rotating one of the roller segments  260  a 180° about the axis  278  in circumferential direction  280  or  282 . Accordingly, two identical roller segments  260  may be manufactured and coupled to the shaft  166  in two configurations. In the first configuration the fins  262  may be aligned with each other along the axis  264 . In the second configuration, the fins  262  may be offset (i.e., staggered) from each other along the axis  264 , which may reduce pulsing (e.g., vibration) of the modular meter roller  28  as the roller segments  260  rotate. The second configuration is illustrated in  FIG. 15  with two superimposed roller segments  260 . As illustrated in the second configuration, the fins  262  on the roller segments  260  are spaced apart by 30° about the axis  264 . In other words, the fins  262  on a first roller segment bisect the 60° angle between the fins  262  on the second roller segment. Depending on the desired stagger, the angle  277  may be changed to create the desired stagger between the roller segments  260  while still enabling production of identical roller segments  260 . 
       FIG. 16  is a cross-sectional view of a roller segment  300 . In  FIG. 16 , the roller segment  300  includes ten fins  302  equally spaced about an axis  304  (e.g., circumferentially). As illustrated, the fins  302  extend from an outer surface  306  of the roller segment  300 , which creates grooves or pockets  308  between the fins  302 . The grooves  308  receive the particulate as the roller segment  300  rotates about the axis  304  during operation of the modular meter roller  28 . The profile of the roller segment  300  between the fins  302  is convex (e.g., convex surface). 
     The roller segment  300  defines an aperture  310  that receives the shaft  166  enabling the roller segment  300  to couple to the modular meter roller  28 . In  FIG. 16 , the aperture  310  is in the form of a hexagon. In other embodiments, the aperture  310  may have a different shape (e.g., octogon, decagon) that corresponds to the shape of the shaft  166 . As explained above, the fins  302  are equally spaced from each other about the axis  304 . The angle  312  between each of the fins  302  is therefore 36°. 
     The fins  302  and the aperture  310  are not aligned. That is, the vertices  314  of the hexagonal aperture  310  do not all align with the axis  316  of the fins  302 . As illustrated, the vertex  314  of the hexagonal aperture  310  are offset from the axis  316  of the proximate fin  302  by the angle  318 . In  FIG. 16 , the angle  318  is half the angle  312  formed by neighboring fins  302  (i.e., 18°). This offset enables staggering (e.g., half-turn staggering) of the fins  302  of two roller segments  300  by rotating one of the roller segments  300  a 180° about the axis  320  in circumferential direction  322  or  324 . Accordingly, two identical roller segments  300  may be manufactured and coupled to the shaft  166  in two configurations. In the first configuration, the fins  302  may be aligned with each other along the axis  304 . In the second configuration, the fins  302  may be offset (i.e., staggered) between roller segments  300  along the axis  304 , which may reduce pulsing (e.g., vibration) of the modular meter roller  28  as the roller segments  300  rotate. Depending on the desired stagger, the angle  318  may be changed to create the desired stagger between the roller segments  300  while still enabling production of identical roller segments  300 . 
       FIG. 17  is a cross-sectional view of a roller segment  340 . In  FIG. 17 , the roller segment  340  includes twelve grooves or flutes  342  equally spaced about an axis  344  (e.g., circumferentially). In operation, the flutes  342  receive the particulate as the roller segment  340  rotates about the axis  344  during operation of the modular meter roller  28 . 
     In order to couple the roller segment  340  to the shaft  166 , the roller segment  340  defines an aperture  346  that receives the shaft  166  enabling the roller segment  340  to couple to the modular meter roller  28 . In  FIG. 17 , the aperture  346  is in the form of a hexagon. In other embodiments, the aperture  346  may have a different shape (e.g., octogon, decagon) that corresponds to the shape of the shaft  166 . As illustrated, the flutes  342  are equally sized and spaced about the axis  344 . The angle  348  between the tips  350  of each of the flutes  342  is therefore 30°. 
     The tips  350  of the flutes  342  do not align with the aperture  346 . That is, the vertices  352  of the hexagonal aperture  346  do not all align with the axis  354  that extends between the flute tips  350  and the axis  344 . As illustrated, the vertex  352  of the hexagonal aperture  310  is offset from the axis  354  of the flute tip  350  by the angle  356 . In  FIG. 17 , the angle  356  is half the angle  348  formed between the flute tips  350  (i.e., 15°). This offset enables staggering (e.g., half-turn staggering) of the flutes  342  of two roller segments  340  by rotating one of the roller segments  340  a 180° about the axis  358  in circumferential direction  360  or  362 . Accordingly, two identical roller segments  340  may be manufactured and coupled to the shaft  166  in two configurations. In the first configuration the flutes  342  may be aligned with each other along the axis  344 . In the second configuration, the flutes  342  may be offset (i.e., staggered) from each other along the axis  344 , which may reduce pulsing (e.g., vibration) of the modular meter roller  28  as the roller segments  340  rotate. Again, depending on the desired stagger, the angle  356  may be changed to create the desired stagger between the roller segments  340  while still enabling production of identical roller segments  340 . 
       FIG. 18  is a cross-sectional view of a roller segment  380 . In  FIG. 18 , the roller segment  380  includes fifteen grooves or flutes  382  equally spaced about an axis  384  (e.g., circumferentially). In operation, the flutes  382  receive the particulate as the roller segment  380  rotates about the axis  384  during operation of the modular meter roller  28 . 
     In order to couple the roller segment  380  to the shaft  166 , the roller segment  380  defines an aperture  386  that receives the shaft  166  enabling the roller segment  380  to couple to the modular meter roller  28 . In  FIG. 18 , the aperture  386  is in the form of a dodgecagon. In other embodiments, the aperture  386  may have a different shape (e.g., hexagon, octogon, decagon) that corresponds to the shape of the shaft  166 . As illustrated, the flutes  382  are equally sized and spaced about the axis  384 . The angle  388  between the tips  390  each of the flutes  382  is therefore 24°. 
     The number of flutes  382  may not correspond to the shape of the aperture  386  therefore the flutes  382  and the aperture  386  may not align. That is, the vertices  392  of the hexagonal aperture  386  do not all align with the axis  394  that extends between the flute tips  390  and the axis  384  (e.g., central axis of the roller segment  380 ). As illustrated, the vertex  392  of the aperture  386  is offset from the axis  394  of the flute tip  390  by the angle  396 . In  FIG. 18 , the angle  396  is half the angle  388  formed between the flute tips  390  (i.e., 15°). This offset enables staggering (e.g., half-turn staggering) of the flutes  382  of two roller segments  380  by rotating one of the roller segments  380  a 180° about the axis  398  in circumferential direction  400  or  402 . Accordingly, two identical roller segments  380  may be manufactured and coupled to the shaft  166  in two configurations. In the first configuration the flutes  382  may be aligned with each other along the axis  384 . In the second configuration, the flutes  382  may be offset (i.e., staggered) from each other along the axis  384 , which may reduce pulsing (e.g., vibration) of the modular meter roller  28  as the roller segments  380  rotate. Again, depending on the desired stagger, the angle  396  may be changed to create the desired stagger between the roller segments  380  while still enabling production of identical roller segments  380 . 
       FIG. 19  is a partial sectional view of roller segments  420  and  422 . As explained above, roller segments (e.g., roller segments  160 ,  260 ,  300 ,  340 , and  380 ) may be staggered, which may reduce pulsing (e.g., vibration) of the modular meter roller  28  and/or the meter system  18 . For example, the roller segments in a modular meter roller  28  may be half-staggered wherein either the fins and/or flutes of a first roller segment are misaligned with the fins and/or flutes of a second roller segment such that the fins and/or flutes of the first roller segment are positioned half-way between the fins and/or flutes of the second roller segment along the shaft. As explained above, the roller segments may be staggered by circumferentially rotating the roller segments about a central axis. This enables identical roller segments to manufactured while still enabling staggering of the roller segments. The staggering is formed by misaligning the fins or flute tips of the roller segments along the axis of the shaft. 
     To facilitate half-staggering the fins and/or flutes, the roller segments  420  and  422  may include respective alignment features  424  and  426 . As seen above, some of the roller segments may define an aperture with a shape that does not have the same number of sides as the number of fins or flutes on the roller segment. Accordingly, the number of positions that enable half-staggering of the roller segments may be one or two circumferential positions. For example, if the roller segment aperture is a hexagon and the number of fins and/or flutes can be evenly divided by 6 (e.g., 12, 18) the roller segments can be aligned, in the manner explained above, without alignment features. However, for roller segments having a number of flutes or fins that are not equal to or evenly divided by the number of the faces of the aperture, the alignment features  424 ,  426  may facilitate half-staggering alignment of the roller segments. For example, the roller segment  300  of  FIG. 16  includes an even number of fins  302  (i.e.,  10 ) and will therefore have two locations for alignment with the hexagonal aperture  310 . In another example, the roller segment  380  of  FIG. 18  includes an odd number of flutes  382  and will therefore have one location for alignment with the dodecagon aperture  386 . The alignment features  424  and  426  may be protrusions, markings (e.g., color codes symbols, symbols, letters, numbers, or combinations thereof). In some embodiments, the alignment feature may be placed on a fin, fin tip, top of a flute, body of the roller segment, and/or a combination thereof to facilitate staggering alignment of roller segments. 
       FIG. 20  is an exploded perspective view of a modular meter roller  28 . As explained above, the modular meter roller  28  enables a user to swap/replace roller segments  450  to accommodate metering of different types of product and/or product sizes (e.g., seed, fertilizer). The illustrated modular meter roller  28  includes three separate roller segments  450  that are configured to couple to a modular shaft  452 . In other embodiments, the modular meter roller  28  may include a different number of roller segments  450  (e.g., one, two, three, four, five, six). Each of these roller segments  450  may differ from the other roller segments  450  (e.g., number of fins, flutes, groove shape, or a combination thereof). In this way, the modular meter roller  28  may enable metering of different products simultaneously or at different times through the metering system  18 . Modularity of the meter roller  28  may also enable the roller segments  450  to couple to the modular shaft  452  in different configurations. That is, the fins and/or flutes of the roller segments  450  may be aligned or staggered when coupled to the modular shaft  452 . As explained above, staggering of the roller segments  450  may reduce and/or block pulsing (e.g., vibration) of the modular meter roller  28  and thus vibration of the meter system  18 . 
     In some embodiments, the modular shaft  452  may include multiple sections that accommodate different apertures of the roller segments  450 . For example, the modular shaft  452  may include a first section  454 . The first section  454  may include an end plate  456  that blocks removal of the roller segments  450  in direction  458 . The first section  454  may also include a first shaft portion  460  that receives a roller segment  450 . As illustrated, the first shaft portion  460  defines a first diameter  462  that may be greater than other shaft portions. Coupled to the first shaft portion  460  is a second shaft portion  464 . The second shaft portion  464  defines a diameter  466 . The second shaft portion  464  is configured to be inserted into an aperture  468  of a second shaft section  470 . The second shaft section  470  is configured to couple to a third shaft section  472  with a shaft connector  474 . In operation, the shaft connector  474  is configured to increase torque transfer from the second shaft section  470  to the third shaft section  472 . The shaft connector  474  includes one or more protrusions  476  that extend (e.g., radially extend) from an exterior surface  478 . The protrusions  476  are configured to interlock or engage protrusions  480  that extend from an end surface  482  of the second shaft section  470 . That is, a first end  484  of the shaft connector  474  is configured to slide into the aperture  468  of the second shaft section  470  to enable the protrusions  476  on the shaft connector  474  to rest in-between the protrusions  480  on the second shaft section  470 . In some embodiments, the shaft connector  474  may define one or more slits  486  that enable fingers  488  of the first end  484  to flex radially inward during insertion of the first end  484  into the second shaft section  470 . 
     In order to couple the third shaft section  472  to the shaft connector  474 , a second end  490  of the shaft connector  474  slides into an aperture  492  of the third shaft section  472 . An end cap  494  completes the modular shaft  452  and couples to the third shaft section  472 . The end cap  494  includes one or more protrusions  496  that extend (e.g., extend radially outward) from an exterior surface  498 . The protrusions  496  are configured to interlock or engage protrusions  500  that extend from an end surface  502  of the third shaft section  472 . In operation, the end cap  494  is configured to slide into the aperture  492  of the third shaft section  472  to enable the protrusions  496  on the end cap  494  to rest in-between the protrusions  500  on the third shaft section  472 . In some embodiments, the end cap  494  may define one or more slits  504  that enable fingers  506  on the end cap  494  to flex radially inward during insertion into the third shaft section  472 . In some embodiments, the end cap  494  may also define grooves  508  in the exterior surface  498 . The grooves  508  may enable the end cap  494  to receive protrusions  510  on an end plate  512 . The protrusions  510  of the end plate  512  extend from the interior surface  514  that defines the aperture  515 . By receiving the protrusions  510  of the end plate  512 , the end cap  494  is able to couple the end plate  512  to the modular shaft  452  and block removal of the roller segments  450 . In some embodiments, the modular shaft  452  may include one or more rods  516  (e.g., heat stakes, self-tapping screws, threaded rods) that may extend through the end plate  456 , the first shaft portion  460 , the second shaft portion  464 , the second shaft section  470 , the third shaft section  472 , and the shaft connector  474  or a subset thereof. After passing through these components of the modular shaft  452 , the rods  516  may then couple to the end cap  494 . For example, the rods  516  may threadingly couple to the end cap  494 . The rods  516  may also be heat stakes that extend through one or more apertures in the end cap  494 . After passing through the end cap  494 , the heat stakes may then be melted to create a head on the rods  516  that blocks their withdrawal through the one or more apertures in the end cap  494 . 
     As illustrated, the modular shaft  452  may define one or more shapes that correspond to the shape of the apertures on the roller segments  450 . For example, the first shaft portion  460  may define a dodecahedron exterior surface profile, while the second and third shaft sections  470  and  472  may define a hexagon exterior surface profile. These exterior surface profiles correspond to the profile of the apertures in the roller segments  450  as well as the discs  518  (e.g., separation discs) and the end plate  512 . 
       FIG. 21  is an exploded perspective view of a modular meter roller  28 . As explained above, the modular meter roller  28  enables a user to swap/replace roller segments  540  to accommodate metering of different types of product and/or product sizes (e.g., seed, fertilizer). The illustrated modular meter roller  28  includes three separate roller segments  540  that are configured to couple to a modular shaft  542 . In other embodiments, the modular meter roller  28  may include a different number of roller segments  540  (e.g., one, two, three, four, five, six). Each of these roller segments  540  may differ from the other roller segments  540  (e.g., number of fins, flutes, groove shape, or a combination thereof). In this way, the modular meter roller  28  may enable metering of different products simultaneously or at different times through the metering system  18 . Modularity of the meter roller  28  may also enable the roller segments  540  to couple to the modular shaft  542  in different configurations. That is, the fins and/or flutes of the roller segments  540  may be aligned or staggered when coupled to the modular shaft  542 . As explained above, staggering of the roller segments  540  may reduce and/or block pulsing (e.g., vibration) of the modular meter roller  28  and thus vibration of the meter system  18 . 
     In some embodiments, the modular shaft  542  may include multiple sections that accommodate different apertures of the roller segments  540 . For example, the modular shaft  542  may include a first section  544 . The first section  544  may include an end plate  546  that blocks removal of the roller segments  540  in direction  548 . The first section  544  may also include a first shaft portion  550  that receives a roller segment  540 . As illustrated, the first shaft portion  550  defines a first diameter  552  that may be greater than other shaft portions. Coupled to the first shaft portion  550  is a second shaft portion  554 . The second shaft portion  554  defines a diameter  556 . The second shaft portion  554  is configured to be inserted into an aperture  558  of a second shaft section  560 . The second shaft section  560  is configured to couple to a third shaft section  562 . Specifically, a first end  564  of the second shaft section  560  is configured to be inserted into an aperture  566  of the third shaft section  562 . As illustrated, the first end  564  defines a width  568 , which is equal to or substantially equal to a width of the aperture  566 . The first end  564  is therefore able to slide into the third shaft section  562  until the lip or ledge  570  contacts the end face  572  of the third shaft section  562 . 
     An end cap  574  completes the modular shaft  542  and couples to the third shaft section  562 . The end cap  574  includes one or more protrusions  576  that extend (e.g., extend radially outward) from an exterior surface  578 . The protrusions  576  are configured to interlock or engage protrusions  580  that extend from an end surface  582  of the third shaft section  562 . In operation, the end cap  574  is configured to slide into the aperture  566  of the third shaft section  562  to enable the protrusions  576  on the end cap  574  to rest in between the protrusions  580  on the third shaft section  562 . In some embodiments, the end cap  574  may define one or more slits  584  that enable fingers  586  of the end cap  574  to flex radially inward during insertion into the third shaft section  562 . In some embodiments, the end cap  574  may also define grooves  588  in the exterior surface  578 . The grooves  588  may enable the end cap  574  to receive protrusions  590  on an end plate  592 . The protrusions  590  of the end plate  592  extend from the interior surface  594  that defines the aperture  596 . By receiving the protrusions  590  of the end plate  592 , the end cap  574  is able to couple the end plate  592  to the modular shaft  542  and block removal of the roller segments  540 . In some embodiments, the modular shaft  542  may include one or more rods  598  (e.g., heat stakes, self-tapping screws, threaded rods) that may extend through the end plate  546 , the first shaft portion  550 , the second shaft portion  554 , the second shaft section  560 , the third shaft section  562 , and the shaft connector  564  or a subset thereof. After passing through these components of the modular shaft  542 , the rods  598  may then couple to the end cap  574 . For example, the rods  598  may threadingly couple to the end cap  574 . The rods  598  may also be heat stakes that extend through one or more apertures in the end cap  574 . After passing through the end cap  574 , the heat stakes may then be melted to create a head on the rods  598  that blocks their withdrawal through the one or more apertures in the end cap  574 . 
     As illustrated, the modular shaft  542  may define one or more shapes that correspond to the shape of the apertures on the roller segments  540 . For example, the first shaft portion  550  may define a dodecahedron exterior surface profile, while the second and third shaft sections  560  and  562  may define a hexagon exterior surface profile. These exterior surface profiles correspond to the profile of the apertures in the roller segments  540  as well as the discs  600  (e.g., separation discs) and the end plate  592 . 
       FIG. 22  is an exploded perspective view of a modular meter roller  28 . As explained above, the modular meter roller  28  enables a user to swap/replace roller segments  620  to accommodate metering of different types of product and/or product sizes (e.g., seed, fertilizer). The illustrated modular meter roller  28  includes three separate roller segments  620  that are configured to couple to a modular shaft  622 . In other embodiments, the modular meter roller  28  may include a different number of roller segments  620  (e.g., one, two, three, four, five, six). Each of these roller segments  620  may differ from the other roller segments  620  (e.g., number of fins, flutes, groove shape, or a combination thereof). In this way, the modular meter roller  28  may enable metering of different products simultaneously through the metering system  18 . Modularity of the meter roller  28  may also enable the roller segments  620  to couple to the modular shaft  622  in different configurations. That is, the fins and/or flutes of the roller segments  620  may be aligned or staggered when coupled to the modular shaft  622 . As explained above, staggering of the roller segments  620  may reduce and/or block pulsing (e.g., vibration) of the modular meter roller  28  and thus vibration of the meter system  18 . 
     In some embodiments, the modular shaft  622  may include multiple sections that accommodate different apertures of the roller segments  620 . For example, the modular shaft  622  may include a first section  624 . The first section  624  may include an end plate  626  that blocks removal of the roller segments  620  in direction  628 . The first section  624  may also include a first shaft portion  630  that receives a roller segment  620 . As illustrated, the first shaft portion  630  defines a first diameter  632  that may be greater than other shaft portions and/or sections. Coupled to the first shaft portion  630  is a second shaft portion  634 . The second shaft portion  634  defines a diameter  636 . The second shaft portion  634  in turn couples to a shaft connector  638 . The shaft connector  638  defines a width  640 . The shaft connector  638  is configured to be inserted into an aperture  642  of a second shaft section  644 . In some embodiments, the shaft connector  638  may include one or more arms or fingers  646  with protrusions  648 . The arms  646  are configured to flex radially inward as the shaft connector  638  is inserted into the second shaft section  644 . The arms  646  slide into the second shaft section  644  until the protrusions  648  align with the apertures  650  in the second shaft section  644 . Once the protrusions  648  align with the apertures  650 , the arms  646  drive the protrusions  648  radially outward and into the apertures  650  forming a connection (e.g., snapfit connection) between the first shaft section  624  and the second shaft section  644 . 
     An end cap  652  completes the modular shaft  622  and couples to the second shaft section  644 . The end cap  652  includes one or more protrusions  654  that extend (e.g., extend radially outward) from an exterior surface  655 . The protrusions  654  are configured to interlock or engage protrusions  656  that extend from an end surface  659  of the second shaft section  644 . In operation, the end cap  652  is configured to slide into the aperture  642  of the second shaft section  644  to enable the protrusions  654  on the end cap  652  to rest in between the protrusions  656  on the second shaft section  644 . In some embodiments, the end cap  652  may include one or more fingers  657  that flex radially inward during insertion into the second shaft section  644 . The fingers  657  include protrusions  658  that are configured to be inserted into the apertures  660  in the second shaft section  644 . Once the protrusions  658  align with the apertures  660 , the fingers  657  drive the protrusions  658  radially outward and into the apertures  660  forming a connection (e.g., snapfit connection) between the end cap  652  and the second shaft section  644 . 
     In some embodiments, the end cap  652  may also define grooves  662  in the exterior surface  655 . The grooves  662  may enable the end cap  652  to receive protrusions  664  on an end plate  668 . The protrusions  664  of the end plate  668  extend from the interior surface  670  that defines the aperture  672 . By receiving the protrusions  664  of the end plate  668 , the end cap  652  is able to couple the end plate  668  to the modular shaft  622  and block removal of the roller segments  620 . As illustrated, the modular shaft  622  may define one or more shapes that correspond to the shape of the apertures on the roller segments  620 . For example, the first shaft portion  630  may define a dodecahedron exterior surface profile, while the second shaft section  644  may define a hexagon exterior surface profile. These exterior surface profiles correspond to the profile of the apertures in the roller segments  620  as well as the discs  674  (e.g., separation discs) and the end plate  668 . 
       FIG. 23  is an exploded perspective view of a modular meter roller  28 . As explained above, the modular meter roller  28  enables a user to swap/replace roller segments  700  to accommodate metering of different types of product and/or product sizes (e.g., seed, fertilizer). The illustrated modular meter roller  28  includes three separate roller segments  700  that are configured to couple to a modular shaft  702 . In other embodiments, the modular meter roller  28  may include a different number of roller segments  700  (e.g., one, two, three, four, five, six). Each of these roller segments  700  may differ from the other roller segments  700  (e.g., number of fins, flutes, groove shape, or a combination thereof). In this way, the modular meter roller  28  may enable metering of different products simultaneously or at different times through the metering system  18 . Modularity of the meter roller  28  may also enable the roller segments  700  to couple to the modular shaft  702  in different configurations. That is, the fins and/or flutes of the roller segments  700  may be aligned or staggered when coupled to the modular shaft  702 . As explained above, staggering of the roller segments  700  may reduce and/or block pulsing (e.g., vibration) of the modular meter roller  28  and thus vibration of the meter system  18 . 
     In some embodiments, the modular shaft  702  may include multiple sections that accommodate different apertures of the roller segments  700 . For example, the modular shaft  702  may include a first section  704 . The first section  704  may include an end plate  706  that blocks removal of the roller segments  700  in direction  708 . The first section  704  may also include a first shaft portion  710  that receives a roller segment  700 . As illustrated, the first shaft portion  710  defines a first diameter  712  that may be greater than other shaft portions and/or sections. Coupled to the first shaft portion  710  is a second shaft portion  714 . The second shaft portion  714  defines a diameter  716 . 
     The second shaft portion  714  couples to an end cap  718  to complete the modular shaft  702 . The end cap  718  includes one or more protrusions  720  that extend (e.g., extend radially outward) from an exterior surface  722 . The protrusions  720  are configured to interlock or engage protrusions  724  that extend from an end surface  726  of the second shaft portion  714 . In operation, the end cap  718  is configured to slide into the aperture  728  of the second shaft portion  714  to enable the protrusions  720  on the end cap  718  to rest in between the protrusions  724  on the second shaft portion  714 . In some embodiments, the end cap  718  may include one or more fingers  730  that flex radially inward during insertion into the second shaft portion  714 . The fingers  730  include protrusions  732  that are configured to be inserted into the apertures  734  in the second shaft portion  714 . Once the protrusions  720  align with the apertures  734 , the fingers  730  drive the protrusions  732  radially outward and into the apertures  734  forming a connection (e.g., snapfit connection) between the end cap  718  and the second shaft portion  714 . 
     In some embodiments, the end cap  718  may also define grooves  736  in the exterior surface  722 . The grooves  736  may enable the end cap  718  to receive protrusions  738  on an end plate  740 . The protrusions  738  of the end plate  740  extend from the interior surface  742  that defines the aperture  744 . By receiving the protrusions  738  of the end plate  740 , the end cap  718  is able to couple the end plate  740  to the modular shaft  702  and block removal of the roller segments  700 . As illustrated, the modular shaft  702  may define one or more shapes that correspond to the shape of the apertures on the roller segments  700 . For example, the first shaft portion  710  may define a dodecahedron exterior surface profile, while the second shaft portion  714  may define a hexagon exterior surface profile. These exterior surface profiles correspond to the profile of the apertures in the roller segments  700  as well as the discs  746  (e.g., separation discs) and the end plate  740 . 
     While only certain features have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the disclosure.