Patent Publication Number: US-2020298053-A1

Title: Modular bicycle trainer

Description:
PRIORITY 
     This application claims the benefit of U.S. Provisional Patent Application No. 62/820,814, filed on Mar. 19, 2019, which is hereby incorporated by reference in its entirety. 
    
    
     BACKGROUND 
     1. Field of the Disclosure 
     The present disclosure is generally directed to a bicycle trainer, and more particularly, to a modular bicycle trainer. 
     2. Description of Related Art 
     Bicycle trainers are known in the art and are typically used for stationary indoor training on a bicycle. Existing or known bicycle trainers are sometimes configured such that a user is not able to use their own bicycle with the trainer. Instead, a bicycle trainer may be a single monolithic machine that is pre-assembled and delivered to a user. While such a bicycle trainer requires little or no assembly by the user, delivery is difficult due to the size, shape, and weight of the pre-assembled bicycle trainer, and customization and upgrade is difficult due to the monolithic nature of the bicycle trainer. Components such as, for example, base support legs, a display, a handlebar mast, and/or a seat mast may be removed for shipping, and a user or a technician may install these components after delivery. 
     SUMMARY 
     In one example, a drive unit for a bicycle trainer includes a housing, a body rotatably attached to the housing, and an axle rotatably attached to the housing. The axle is operatively connected to the body, such that the body is driveable via the axle. The drive unit also includes a motion resistor supported by the housing. The motion resistor is configured to apply a resistive force to the body when the body is rotating. The drive unit includes a first guide within or supported by the housing. The first guide corresponds to a second guide. The second guide is disposed on a frame of the bicycle trainer. 
     In one example, the first guide includes a plurality of openings through a portion of the frame. The second guide includes a plurality of captive fasteners. The drive unit is positionable on the frame, such that the plurality of captive fasteners extend through the plurality of openings. 
     In one example, the body is a flywheel. 
     In one example, the drive unit further includes a wheel rotatably attached to the housing. An axis of rotation of the wheel is in line with an axis of rotation of the axle. A diameter of the wheel is larger than a diameter of the flywheel. The drive unit further includes a belt or a chain disposed around the wheel. The axle is operatively connected to the flywheel via the wheel and the belt or the chain. 
     In one example, the wheel is a first wheel. The drive unit further includes a second wheel rotatably attached to the housing. An axis of rotation of the second wheel is in line with an axis of rotation of the flywheel. A diameter of the second wheel is smaller than the diameter of the first wheel and the diameter of the flywheel. The belt or the chain is disposed around the second wheel. The axle is operatively connected to the flywheel via the first wheel, the belt or the chain, and the second wheel. 
     In one example, the motion resistor includes an electromagnet supported by the housing at a fixed distance relative to the flywheel, a permanent magnet supported by the housing at a variable distance relative to the flywheel, a generator, or a mechanical motion resistor that is movable into contact with the flywheel. 
     In one example, the motion resistor includes the mechanical motion resistor. The mechanical motion resistor includes a plunger that is movable into contact with the flywheel. 
     In one example, the housing has a first portion and a second portion. The second portion of the housing extends away from a side of the first portion of the housing. The first guide is disposed within the second portion of the housing. 
     In one example, the second portion of the housing weighs at least as much as a remainder of the drive unit. 
     In one example, the flywheel is attached to the housing at or adjacent to the side of the first portion of the housing, such that the flywheel and the second portion of the housing are disposed on a same side of the first portion of the housing. 
     In one example, the side of the first portion of the housing is a first side of the first portion of the housing. The wheel is attached to the housing at or adjacent to a second side of the first portion of the housing. The second side of the first portion of the housing is opposite the first side of the first portion of the housing. 
     In one example, the axle extends through at least part of the first portion of the housing and at least part of the second portion of the housing. 
     In one example, a bicycle trainer includes a drive unit and a frame. The drive unit includes a housing, a drivable flywheel rotatably attached to the housing, and a motion resister supported by the housing. The motion resister is configured to apply a force to the drivable flywheel. The drive unit also includes a first guide within or supported by the housing. The frame includes one or more supports and a second guide within or supported by the one or more supports, the second guide corresponds to the first guide. The drive unit is removably attached to the frame via the first guide and the second guide. 
     In one example, the first guide includes a plurality of holes through a portion of the housing of the drive unit. The second guide includes a plurality of captive fasteners extending away from a support of the one or more supports. The plurality of captive fasteners extend through the plurality of holes, and the portion of the housing of the drive unit abuts the support of the frame when the drive unit is attached to the frame. 
     In one example, the support is a first support. The one or more supports further include a second support and a third support forming a v-shape. The first support extends between the second support and the third support, such that a length of the first support defines a position of the first support and the drive unit along the second support and the third support. 
     In one example, the motion resister includes an electromagnet supported by the housing at a fixed distance relative to the drivable flywheel, a permanent magnet supported by the housing at a variable distance relative to the drivable flywheel, a generator, or a mechanical motion resistor that is movable into contact with the drivable flywheel. 
     In one example, the housing has a first portion and a second portion. The second portion of the housing extends away from a side of the first portion of the housing. The first guide is disposed within the second portion of the housing. The drivable flywheel is attached to the first portion of the housing at or adjacent to the side of the first portion of the housing, such that the drivable flywheel and the second portion of the housing are disposed on a same side of the first portion of the housing. 
     In one example, a frame for a bicycle trainer includes two supports, a mounting plate extending between the two supports, and one or more captive fasteners extending away from the mounting plate. The one or more captive fasteners correspond to one or more openings through a housing of a drive unit, respectively. The drive unit includes a drivable flywheel rotatably attached to the housing, and a motion resister supported by the housing and configured to apply a force to the flywheel. 
     In one example, the one or more captive fasteners include a plurality of captive fasteners extending away from the mounting plate. The one or more openings through the housing of the drive unit include a plurality of openings through the housing of the drive unit. The plurality of openings correspond to the plurality of captive fasteners, respectively. 
     In one example, the two supports form a v-shape. The mounting plate extends between the two supports, such that a length of the mounting plate defines a position of the mounting plate along the two supports. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Objects, features, and advantages of the present invention will become apparent upon reading the following description in conjunction with the drawing figures, in which: 
         FIG. 1  shows a perspective view of one example of a drive unit; 
         FIG. 2  shows a close-up perspective view of one example of an attachment portion of a housing of the drive unit of  FIG. 1 ; 
         FIG. 3  shows a perspective view of one example of a mount positioned on a frame portion of a modular bicycle trainer; 
         FIG. 4  shows a close-up perspective view of one example of a mount positioned on a frame portion of a modular bicycle trainer and including fasteners; 
         FIG. 5  shows a first perspective view of one example of a drive unit and a frame portion of a modular bicycle trainer in an attached state; 
         FIG. 6  shows a second perspective view of one example of a drive unit and a frame portion of a modular bicycle trainer in an attached state; 
         FIG. 7  shows a front view of one example of a drive unit and a frame portion of a modular bicycle trainer in an attached state; and 
         FIG. 8  shows a perspective view of one example of a modular bicycle trainer. 
     
    
    
     DETAILED DESCRIPTION OF THE DISCLOSURE 
     The modular bicycle trainer of the present embodiments separates components of a bicycle trainer into modules that correspond with functional systems. This allows for easier design, easier shipping, and simple assembly and upgrade to the functional systems over a lifetime of the bicycle trainer. 
     Characteristics of the modular bicycle trainer may define separation of the modules. For example, rider touchpoints and/or engineering interaction may define the separation of the modules. With respect to rider touchpoint, the rider interacts with the modular bicycle trainer at a discrete number of touch points: feet, hands, seat, and eyes. Boundaries of the modules may be defined by the engineering systems that serve each of the discrete number of touch points. With respect to engineering interaction, the modules may maximize the engineering complexity contained within each of the modules, while engineering complexity of interfaces and/or interactions between the modules is minimized. 
     The modular bicycle trainer of the present embodiments may include any number of modules including, for example, a frame, a drive unit assembly, a handlebar assembly, a seat assembly, and a console. The modular bicycle trainer may include more, fewer, and/or different modules. 
     The drive unit assembly includes components used to create resistance and road feel at the feet of the user. For example, a drive unit includes a flywheel mass, an adjustable load device, an electronic controller, one or more adjustable load sensors, one or more drive pulleys or chainrings, a belt or chain tensioning device, a belt or chain, crank arms, and pedals. The drive unit may include more, fewer, and/or different components. For example, the drive unit may also include bearings and shrouds. In one embodiment, the drive unit may be a direct design where the crank arms drive a flywheel or a load unit directly without a belt or a chain. In another embodiment, the crank arms may drive the load unit through a gearbox (e.g., a planetary gear system). 
     The drive unit is attached to the frame in a simple and secure manner. Mounting points and dimensional control of a drivetrain are included within the drive unit. A number of fasteners used to attach the drive unit to the frame is minimized. For example, guide pins and/or another locator aids alignment and makes it easy for the user to properly install the drive unit on the frame. 
     The frame and the drive unit are each heavy (e.g., 40 lbs. or more each) and bulky. Due to the modular nature of the bicycle trainer of the present embodiments, the frame and the drive unit may be shipped to the user separately and assembled by the user after delivery. If the modular bicycle trainer is to be moved a significant distance during the lifetime of the modular bicycle trainer, the modular bicycle trainer may be disassembled, moved, and reassembled by the user. 
     Turning now to the drawings,  FIG. 1  illustrates a perspective view of one example of a drive unit  50 . The drive unit  50  includes a housing  52  (e.g., a swing arm) that supports a drive  54  (e.g., an axle or a spindle), a load unit  56 , and one or more other components (see  FIGS. 6 and 7 ). The load unit  56  includes, for example, a flywheel  58  (e.g., a rotatable body) that is rotationally coupled to (e.g., directly or indirectly) the drive  54  (see  FIGS. 6 and 7 ) and electronics  60  configured to control the load unit  56 . Crank arms with pedals (not shown) are attachable to opposite sides of the drive  54 , such that the user may pedal the modular bicycle trainer. 
     The electronics  60  are positioned on and/or supported by, for example, a support  62 . The support  62  is, for example, a plate that is removably attached to the housing  52  of the drive unit  50 . In other embodiments, the support  62  is configured differently. For example, the support  62  may be a printed circuit board (PCB). In another example, the support  62  is part of the housing  52 . 
     The plate  62  is removably attached to the housing  52  of the drive unit  50  with, for example, one or more connectors  64  (e.g., screws and/or nut/bolt combinations). In one embodiment, the plate  62  is attached to the housing  52  of the drive unit  50  such that distances between components supported by the plate  62  (e.g., a permanent magnet or an electromagnet) and the flywheel  58  may be varied. In one embodiment, the drive unit  50  includes an actuator (e.g., an electric motor) configured to move the plate  62  and/or a component supported by the plate (e.g., the permanent magnet or the electromagnet) away from and towards the flywheel  58 . In other embodiments, the plate  62  may be removably attached to other components of the modular bicycle trainer such as, for example, the frame. 
     The electronics  60  include any number of components including, for example, an electromagnet  66 . The electromagnet  66  may include a plurality of wires  68  wrapped around and/or disposed on a core  70  of a magnetic material. The electromagnet  66  is magnetically coupled with a permanent magnet or a magnetic material on the flywheel  58 . In one embodiment, positioning of the electromagnet  66  and the permanent magnet are reversed: The electromagnet  66  is positioned on the flywheel  58 , and the permanent magnet is positioned on the plate  62 . In one embodiment, the electromagnet  66  is formed on opposite sides of the core  70 . In yet another embodiment, a plurality of cores  70  (e.g., two cores on opposite sides of the flywheel  58 ) are attached to the plate  62 , and a plurality electromagnets  66  are formed on the plurality of cores  70 . 
     Current flows from a source external to the drive unit and through the electromagnet  66  via a lead line  72  and a connector  74 . The source may be at the wall in a location at which the modular bicycle trainer is installed or a power source (e.g., a battery) on or separate from the modular bicycle trainer. The connector  74  may be directly or indirectly (e.g., via one or more intermediate components) connected to the source. 
     In other embodiments, the current flows from the external source and is controlled for other types of movement resistors. For example, the current may be controlled to activate a motor to change a distance between a permanent magnet on the plate  62  and the flywheel  58 , to power a generator with windings on the flywheel  58  and the plate  62 , respectively, and/or to activate an actuator configured to move a plunger into towards the flywheel  58 . 
     The electromagnet  66  generates a magnetic field when the source is connected to the electromagnet  66  via the lead line  72  and the connector  74  and current flows through the plurality of wires  68 . The magnetic field interacts with the flywheel  58  (e.g., made of an electrically conductive material) and resists rotation of the flywheel  58 . The electromagnet  66 , when interacting with the permanent magnet or the magnetic material of the flywheel  58 , acts, for example, as a motion resistor with respect to the flywheel  58 . Rotation of the drive  54  rotationally coupled to the flywheel  58  is thus also resisted. An amount of rotational resistance may be set based on a power provided by the source to the electromagnet and/or a distance between the electromagnet  66  and the permanent magnet or the magnetic material of the flywheel  58 . In one embodiment, the rotational resistance is provided mechanically. For example, a plunger with a felt tip (e.g., the motion resister) is in contact with a surface (e.g., a circumferential surface or a radial surface) of the flywheel  58  to resist rotation of the flywheel  58  with friction. The amount of rotational resistance may be set based on a force applied to the surface of the flywheel  58  by the rotational resistor. Other mechanical motion resisters may be provided. For example, calipers may squeeze pads against opposite sides of the flywheel  58 . 
     In other embodiments, the rotational resistance may be provided by a permanent magnet supported by the housing  52  and/or the plate  62  at a variable distance relative to the flywheel  58  (e.g., via a servo motor), and/or a generator with stator windings supported by the housing  52  and/or the plate  62 , and rotor windings supported by the flywheel  58 . The drive unit  50  may provide the rotational resistance in more than one of these ways (e.g., with the electromagnet  66  and the mechanical motion resister). 
     The electronics  60  may also include a PCB  76  supported by the plate  62 . The PCB  76  may support and electrically connect any number of electronic components including, for example, a processor, a memory, one or more communication devices (e.g., a wireless transmitter, antennas), one or more sensors, and/or other electronic components. The processor may be in communication with electronic components (e.g., one or more communication devices) of a handlebar assembly via the one or more communication devices. The one or more communication devices of the drive unit  50  may be paired with the one or more communication devices of the handlebar assembly and/or other modules of the modular bicycle trainer prior to communication between, for example, the drive unit  50  and the handlebar assembly. The processor may determine a power to be provided by the source and/or how much resistance to the rotation of the flywheel  58  is to be provided (e.g., a proximity of the plate  62  relative to the flywheel  58 , power to be provided to the motor moving the plunger, and/or power to be provided to the generator) to be provided based on data received from the electronic components of the handlebar assembly. 
     For example, the processor may determine the power to be provided based on a user input (e.g., generated in response to the user pressing a resistance up button at the handlebar assembly) and instruct a communication device electrically connected to the processor via the PCB  76  to transmit the determined power to a communication device (e.g., a wireless transmitter, antennas) associated with the source and/or a controller configured to control current to the electromagnet  66 . In another example, the processor determines a distance between, for example, a permanent magnet and the flywheel  58  to be provided based on the user input and instructs the communication device to transmit the determined distance to a communication device associated with a controller configured to control the actuator that moves the plate  62  and/or the core  70 . The amount of rotational resistance may thus be controlled based on user input at, for example, the handlebar assembly. 
     The drive unit  50  is attached to the frame of the modular bicycle trainer via an attachment portion  80  of the housing  52 . For example, a remainder of the housing  52  (e.g., excluding the attachment portion  80  of the housing  52 ) forms a first portion  81  of the housing  52 , and the attachment portion  80  of the housing  52  forms a second portion of the housing  50 . The housing  52  has an outer surface  82  from which the attachment portion  80  extends. In other words, the second portion  80  of the housing  52  extends away from a side (e.g., a first side) of the first portion  81  of the housing  52 . The attachment portion  80  may be formed contiguously with the housing  52  or may be separate from and attached to the housing  52  in any number of ways (e.g., with one or more fasteners). 
     The drive unit  50  may be heavy (e.g., 25-50 lbs) and may be an irregular shape with a center of gravity at a position displaced from a frame mounting location. As discussed below, a mount for mounting the drive unit  50  to the frame may include captive fasteners (e.g., threaded bolts) or pins, allowing initial positioning of the drive unit  50  on the frame with gravity, not with the tightening of nuts, for example, on the threaded bolts. Alternatively, the attachment portion  80  may weigh as much as or more than the rest of the drive unit  50  such that the drive unit  50  may be positioned on the mount without the drive unit  50  tipping over relative to the frame. This may facilitate attachment of the drive unit  50  on the frame by the user. 
     Referring to  FIG. 2 , the attachment portion  80  includes one or more openings  84  (e.g., a first guide) to further facilitate attachment of the drive unit  50  on the frame. The one or more openings  84  may be through holes or blind holes. The one or more openings  84  may be threaded or unthreaded. 
     As shown in the example of  FIG. 2 , the attachment portion  80  includes four openings  84  extending from a first side  86  of the attachment portion  80 , through the attachment portion  80 , to a second side  88  of the attachment portion  80  opposite the first side  86 . The drive  54  extends at least partially through the attachment portion  80  and at least partially through the first portion  81  of the housing  52 . In one example, the drive  54  extends all the way through the attachment portion  80  and the first portion  81  of the housing  52  (e.g., all the way through the housing  52 ). The drive  54  is, for example, a spindle, and ends of the spindle  54  are shaped and sized to facilitate attachment of crank arms with pedals for use of the modular bicycle trainer by the user. 
     The four openings  84  include two first openings  84   a  adjacent to a first edge  90  and two second openings  84   b  adjacent to a second edge  92  opposite the first edge  90 . Positioning of the first openings  84   a  and the second openings  84   b  is symmetrical about the spindle  54  extending through the attachment portion  80 . The attachment portion  80  may include more or fewer openings  84 , and/or the openings  84  may be positioned differently relative to each other and/or relative to the first edge  90  and/or the second edge  92 . 
     Referring to  FIG. 3 , the openings  84  through the attachment portion  80  of the housing  52  may correspond to openings  94  (e.g., four openings) through a mount  96  for the drive unit  50  supported by a frame  100  of the modular bicycle trainer. The openings  94  through the mount  96  at least partially form a second guide (e.g., with captive fasteners). The frame  100  of the modular bicycle trainer includes a base  102  and one or more supports  104  extending away from the base  102 . For example, the one or more supports  104  include two supports  104  extending in directions away from the base  102 , such that the two supports  104  form a V-shape. The two supports  104  may form a V-shape in that the two supports  104  extend away from each other from the base  102  (e.g., with or without contacting each other). A seat assembly may be attached to a first support  104   a  of the two supports  104 , and a handlebar assembly may be attached to a second support  104   b  of the two supports  104 . 
     The mount  96  may be configured in any number of ways including, for example, as a mounting plate. The first support  104   a  of the frame  100 , the second support  104   b  of the frame  100 , and/or the mounting plate  96  may include notches and/or the mounting plate  96  may be sized (e.g., of a particular length) such that positioning of the mounting plate  96  in a predetermined position and orientation (e.g., with desired tolerances) relative to other mounting locations on the frame (e.g., for the seat assembly and the handlebar assembly) is facilitated. Once the mounting plate  96  is positioned in the predetermined position and orientation, the mounting plate  96  may be attached to the first support  104   a  and/or the second support  104   b  in any number of ways including, for example, with one or more connectors (e.g., fasteners). Alternatively, the attachment of the mounting plate  96  to the first support  104   a  and the second support  104   b  may be a friction fit attachment. 
     In one embodiment, the first support  104   a  and the second support  104   b  include a number of sets of notches at different heights relative to the base  102 , respectively. Different sized mounting plates  96  (e.g., with different lengths) may then be used depending on the height of the notches used relative to the base  102 . For example, the length of the mounting plate  96  may define a position of the mounting plate  96 , and thus the drive unit  50 , along the first support  104   a  and the second support  104   b.    
     Referring to  FIG. 4 , connectors  120  may extend through the openings  94  through the mount  96  and the openings  84  through the attachment portion  80  of the housing  52  of the drive unit  50 . When the attachment portion  80  of the housing  52  of the drive unit  50  is attached to the mount  96  via the connectors  120  through the openings  84  through the attachment portion  80  of the housing  52  of the drive unit  50 , the attachment portion  80  may abut the mount  96 . 
     The number of connectors  120  may be equal to the number of openings  94  through the mount  96  and the number of openings  84  through the attachment portion  80  of the housing  52  of the drive unit  50 . Alternatively, the number of connectors  120  may be less than the number of the openings  94  through the mount  96  and/or the number of the openings  84  through the attachment portion  80  of the housing  52  of the drive unit  50 . 
     The connectors  120  may include any number of different types of connectors (e.g., fasteners) including, for example, threaded bolts  122 . The connectors  120  may include captive fasteners that are captive at the mounting plate  96  (e.g., captive threaded bolts  122 ). Other connectors  120  may be used. For example, alternative or in addition to the threaded fasteners, the connectors  120  may include clamps (e.g., over-center clamps), circular or other geometric interlocking geometries, quick release mechanisms, guide pins, and/or other connectors. 
       FIG. 5  shows one example of the drive unit  50  and the frame  100  in an attached state. In the example shown, the drive unit  50  is attached to the frame  100  with the threaded bolts  122  and threaded nuts  124 . In one embodiment, the threaded nuts  124  include tapered ends (e.g., similar to a tapered lug nut on a wheel of a road vehicle), respectively, that engage the attachment portion  80  of the housing  52  of the drive unit  50 . The attached state using, for example, the threaded bolts  122  and the threaded nuts  124 , is a rigid attachment. The drive unit  50  does not flex or move relative to the frame outside of a predetermined tolerance during operation of the modular bicycle trainer, even under heavy load. 
     During assembly of the modular bicycle trainer, the user places the drive unit  50  in a predetermined position relative to the frame  100  by positioning the drive unit  50  over the mounting plate  96 , aligning the threaded bolts  122 , for example, with the openings  84  through the attachment portion  80  of the housing  52  of the drive unit  50 , and moving the drive unit  50  onto the mounting plate  96  such that the threaded bolts  122  extend through the openings  84  through the attachment portion  80  of the housing  52  of the drive unit  50 . In such an attachment, the drive unit  50  is not sufficiently rigidly attached to the frame  100  for operation of the modular bicycle trainer, but the drive unit  50  is located and will not tip or fall off of the frame  100 . The user may then use both hands to install the threaded nuts  124 , for example, on the threaded bolts  122  and rigidly secure the drive unit  50  to the frame  100 . 
     Referring to  FIGS. 6 and 7 , the one or more other components of the drive unit  50  include a large pulley  140  (e.g., a large wheel) rotationally coupled to the drive  54  (e.g., via a direct connection such that an axis of rotation of the large pulley  140  is in line with an axis of rotation of the drive  54 ) and a small pulley  142  (e.g., a small wheel) rotationally coupled to the large pulley  140 . The small pulley  142  is rotationally coupled to the large pulley  140  with, for example, a belt or a chain  144 . The small pulley  142  is rotationally coupled with the flywheel  58  (e.g., via a direct connection such that an axis of rotation of the flywheel  58  is in line with an axis of rotation of the small pulley  142 ). The one or more other components of the drive unit  50  may include any number of additional and/or different components including, for example, an additional pulley  146  (e.g., an idler pulley). The additional pulley  146 , for example, is rotationally coupled to the large pulley  140  and the small pulley  142  with the belt or the chain  144 . The large pulley  140 , the small pulley  142 , and, for example, the additional pulley  146  are rotatably supported by the housing  52  of the drive unit (e.g., via bearings attached to the housing  52 ). 
     In one embodiment, a diameter of the large pulley  140  is larger than a diameter of the flywheel  58  and larger than a diameter of the small pulley  142 ; the diameter of the flywheel  58  is larger than the diameter of the small pulley  142 . The flywheel  58 , the large pulley  140 , and the small pulley  142  may be made of any number of materials. For example, the flywheel  58 , the large pulley  140 , and the small pulley  142  may be made of aluminum. One or more of the flywheel  58 , the large pulley  140 , and the small pulley  142  may be made of different materials. 
     All mounting locations of, for example, the large pulley  140 , the small pulley  142 , the additional pulley  146 , the flywheel  58 , the electromagnet  66 , the core  70 , the plate  62 , the electromagnet  66 , and/or other components of the drive unit  50  are within or on the housing  52  (e.g., the first portion  81  of the housing  52 ) of the drive unit  50 . In other words, none of the mounting locations of, for example, the large pulley  140 , the small pulley  142 , and the additional pulley  146  are on the frame  100 . These components may be preassembled (e.g., prior to shipping to the user) and thus part of the drive unit  50  module. Accordingly, dimensional control locations and tolerances for these components are isolated to the drive unit  50 . 
     In the embodiment shown in  FIGS. 6 and 7 , the attachment portion  80  and the flywheel  58  are disposed on a same side of the first portion  81  of the housing  52  (e.g., at or adjacent to the first side of the first portion  81  of the housing  52 ), and the large pulley  140 , the small pulley  142 , the additional pulley  146 , and the belt or chain  144  are disposed on a same other side of the first portion  81  of the housing  52  (e.g., at or adjacent to a second side of the first portion  81  of the housing  52 , which is opposite the first side of the first portion  81  of the housing  52 ). 
     The drive unit  50  may include additional components. For example, the drive unit  50  includes safety shrouds that protect the user from injury at the large pulley  140 , the small pulley  142 , the additional pulley  146 , the flywheel  58 , and/or additional pinch points. All of the safety shrouds and other protection devices may be attached to the drive unit  50  such that all corresponding dimensional control is provided in the drive unit  50 . 
       FIG. 8  shows one example of a modular bicycle trainer  200 . The modular bicycle trainer  200  of the present embodiments may include any number of modules including, for example, the frame  100 , a drive unit assembly (e.g., the drive unit  50 ), a handlebar assembly  201  (e.g., control bars), a seat assembly  202 , and a console  204 . The modular bicycle trainer  200  may include more, fewer, and/or different modules. 
     The frame  100  includes, for example, two supports (e.g., the first support  104   a  and the second support  104   b ), the base  102  including base support legs  206   a ,  206   b , and  206   c , a seat mast  208 , a handlebar mast  210 , a console mount  212 , and an electronic device mount (e.g., for a tablet or phone). The frame  100  may include more, fewer, and/or different components. For example, the frame  100  may also include water bottle mounts and/or exercise accessory mounts (e.g., for weights). As another example, the frame  100  may include more or fewer supports  104  and/or base support legs  206  and/or different supports  104  and/or base support legs  206  (e.g., different shapes). 
     The frame  100  includes mounting locations for the other modules. Mounting mechanisms (e.g., the mount  96  and the fasteners  120 ) for mounting the other modules are configured to minimize complexity of assembly. The frame  100  may be further disassembled to reduce a volume during shipping, while allowing for reassembly by the user. 
     The handlebar assembly  201  includes primary surfaces and controls  216  the user (e.g., the rider) uses while riding the modular bicycle trainer  200 . For example, the handlebar assembly  201  includes a handlebar mount  218  (e.g., a mounting mechanism), a handlebar  220 , and the user controls  216 . The handlebar assembly  201  may include more, fewer, and/or different components. 
     In an embodiment, in which the handlebar assembly  201  includes the mounting mechanism  218 . the mounting mechanism  218  allows the handlebar  220  to be attached to the handlebar mast  210 . The mounting mechanism  218  is configured so that the user may detach and reattach the handlebar assembly  201  quickly and without tools. This allows multiple users to use a same modular bicycle trainer  200  with multiple different handlebars  220  (e.g., corresponding to the different users). 
     Electronic components of the handlebar assembly  201  are connected to the drive unit  50 , the console  204 , and/or other electronics via wired or wireless communication. The handlebar assembly  201  may be powered through a wired power supply, batteries, and/or in another way. Electronic technology and controls for bicycle trainers may evolve over time. The modular design of the handlebar assembly  201  allows the user to upgrade the handlebar assembly  201  over the life of the bicycle trainer  200  to a newer generation handlebar assembly  201  with different or improved electronic technology and/or controls. 
     The seat assembly  202  includes, for example, a seat mount  222  (e.g., a saddle mount mechanism) and a seat  224  (e.g., a saddle). The seat assembly  202  may include more, fewer, and/or different components. 
     The saddle mount mechanism  222  allows the seat assembly  202  to be attached to the seat mast  208 . The saddle mount mechanism  222  is configured so that the user may detach and reattach the seat assembly  202  quickly and without tools. This allows multiple users to use the same modular bicycle trainer  200  with multiple different seats  224  (e.g., corresponding to the different users). The saddle mount mechanism  222  may preserve an angle or a tilt of the saddle  224  between installations, as this may be an important adjustment for comfort while riding. 
     The modular bicycle trainer  200  of the present disclosure may include the console  204  (e.g., including one or more displays). The console  204  may include, for example, a display screen, a computer processing unit (CPU), and wired or wireless networking equipment. The console  204  may include more, fewer, and/or different components. For example, the console  204  may include secondary user controls such as volume up and down and/or a power control. The console  204  mounts to the frame  100  and is powered by an external source or batteries. The console  204  communicates with other electronic systems of the modular bicycle trainer  200  (e.g., the handlebar assembly and/or the drive unit) wirelessly and/or via one or more wired connections 
     The illustrations of the embodiments described herein are intended to provide a general understanding of the structure of the various embodiments. The illustrations are not intended to serve as a complete description of all of the elements and features of apparatus and systems that utilize the structures or methods described herein. Many other embodiments may be apparent to those of skill in the art upon reviewing the disclosure. Other embodiments may be utilized and derived from the disclosure, such that structural and logical substitutions and changes may be made without departing from the scope of the disclosure. Additionally, the illustrations are merely representational and may not be drawn to scale. Certain proportions within the illustrations may be exaggerated, while other proportions may be minimized. Accordingly, the disclosure and the figures are to be regarded as illustrative rather than restrictive. 
     While this specification contains many specifics, these should not be construed as limitations on the scope of the invention or of what may be claimed, but rather as descriptions of features specific to particular embodiments of the invention. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable sub-combination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a sub-combination or variation of a sub-combination. 
     Similarly, while operations and/or acts are depicted in the drawings and described herein in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the embodiments described above should not be understood as requiring such separation in all embodiments, and it should be understood that any described program components and systems can generally be integrated together in a single software product or packaged into multiple software products. 
     One or more embodiments of the disclosure may be referred to herein, individually and/or collectively, by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any particular invention or inventive concept. Moreover, although specific embodiments have been illustrated and described herein, it should be appreciated that any subsequent arrangement designed to achieve the same or similar purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all subsequent adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, are apparent to those of skill in the art upon reviewing the description. 
     The Abstract of the Disclosure is provided to comply with 37 C.F.R. § 1.72(b) and is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, various features may be grouped together or described in a single embodiment for the purpose of streamlining the disclosure. This disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter may be directed to less than all of the features of any of the disclosed embodiments. Thus, the following claims are incorporated into the Detailed Description, with each claim standing on its own as defining separately claimed subject matter. 
     It is intended that the foregoing detailed description be regarded as illustrative rather than limiting and that it is understood that the following claims including all equivalents are intended to define the scope of the invention. The claims should not be read as limited to the described order or elements unless stated to that effect. Therefore, all embodiments that come within the scope and spirit of the following claims and equivalents thereto are claimed as the invention.