Patent Publication Number: US-2023149761-A1

Title: Noise reduction assembly for motor-driven exercise device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is related to and claims priority under 35 U.S.C. § 119(e) from U.S. Patent Application No. 63/278,813, filed Nov. 12, 2021, titled “Noise Reduction Assembly for Moto-Driven Exercise Device”, the entire contents of which are incorporated herein by reference for all purposes. 
    
    
     TECHNICAL FIELD 
     Aspects of the present invention are directed to exercise devices and, in particular, to noise and vibration reduction in motor-driven exercise devices. 
     BACKGROUND 
     The benefit of regular exercise is undisputed. Nonetheless, beginning and maintaining a successful exercise regimen is a challenge for many individuals for a variety of reasons. For example, simply finding the time to begin an exercise program is a challenge. Finding an exercise, or more preferably exercises, suitable for an individual and his or her personal fitness goals is a further complication given that many people have insufficient knowledge as to different types of exercises, the benefits of different exercise, and how to perform those exercises. With time constraints and a lack of knowledge, users may also fail to properly track and analyze performance and progress, leading to lackluster development and impacting motivation to maintain an exercise program. As a result, there is an ongoing need to develop efficient exercise devices that provide ways to easily perform exercises correctly with optimal resistance to maximize results in minimal time. 
     While exercising at home may increase the likelihood of a person staying within an exercise regime, professional grade exercise equipment is often large and cumbersome and is often designed for only a small set of exercises. While exercise devices with form factors suitable for home use exist, such equipment often lacks the robustness of professional grade equipment, negatively impacting the efficiency of such devices and introducing vibrations and instability that significantly impact user experience and, in certain cases, the effectiveness and safety of exercises performed using such devices. 
     It is with these observations in mind, among others, that aspects of the present disclosure were developed. 
     SUMMARY 
     A first aspect of this disclosure is directed to an exercise device including a housing having a top portion and a bottom portion and an internal frame disposed within the housing. The internal frame includes a web extending between the top portion and the bottom portion. The exercise device further includes a dampening block coupled to the web and a motor including a motor casing and a shaft. The shaft is supported by the dampening block and rotationally fixed by the dampening block. The exercise device further includes a cable pulley coupled to the motor casing such that, when the motor is actuated, each of the motor casing and the cable pulley rotate. 
     In certain implementations the dampening block includes a shaft coupling assembly. In such implementations, the shaft extends into the shaft coupling assembly and is rotationally fixed by the shaft coupling assembly and the exercise device further includes a dampening pad disposed between the shaft coupling assembly and the web. 
     In other implementations the dampening block includes a shaft coupling assembly. In such implementations, the shaft coupling assembly includes a block defining a channel and the shaft extends along the channel. The shaft coupling assembly further includes a cover plate abutting the block and covering the channel. The shaft includes a flat within which a portion of the cover plate is disposed to rotationally fix the shaft. The exercise device further includes a dampening pad disposed between the shaft coupling assembly and the web. 
     In other implementations the techniques described herein relate to an exercise device further including a bracket coupled to each of the dampening block and the internal frame, wherein the dampening block includes a shaft coupling assembly and a dampening pad disposed between the bracket and the shaft coupling assembly. 
     In other implementations the exercise device further includes a bracket and the internal frame further includes a transverse member offset from the web. In such implementations, the bracket is coupled to each of the dampening block and the transverse member. 
     In other implementations the exercise device further includes a bracket and the internal frame further includes a transverse member offset from the web and disposed adjacent the top portion. In such implementations, the bracket is coupled to each of the dampening block and the transverse member. 
     In other implementations the exercise device further includes an encoder supported by the web. The cable pulley is coupled to the encoder by a flexible shaft coupling and the encoder is configured to measure rotation of the cable pulley. 
     In other implementations the motor is a brushless direct current (BLDC) motor and the exercise device further includes a motor controller to actuate the motor using trapezoidal commutation. 
     In other implementations, the web is coupled to each of the top portion and the bottom portion. 
     Another aspect of the present disclosure is directed to an exercise device including a housing and a motor including a motor casing and a shaft. The shaft is rotationally fixed within the housing by a dampened connection and supports the motor casing within the housing. The exercise device further includes a cable pulley extending from the motor casing such that, when the motor is actuated, each of the motor casing and the cable pulley rotate. 
     In certain implementations the exercise device further includes an internal frame disposed within the housing and the dampened connection includes a dampening block coupled to the internal frame. 
     In other implementations the exercise device further includes an internal frame disposed within the housing and the internal frame includes a web extending between a top portion of the housing and a bottom portion of the housing. In such implementations the dampened connection includes a dampening block coupled to the web. 
     In other implementations the exercise device further includes an internal frame disposed within the housing and the dampened connection includes a dampening block coupled to the internal frame and a bracket coupled to and extending between each of the dampening block and the internal frame. 
     In other implementations the exercise device further includes an internal frame disposed within the housing and the dampened connection includes a dampening block coupled to a transverse web of the internal frame. The dampened connection further includes a bracket coupled to and extending between each of the dampening block and a transverse member of the internal frame offset from the transverse web. 
     In other implementations the exercise device further includes an internal frame disposed within the housing and the internal frame includes a web extending between a top portion and a bottom portion of the housing with the dampened connection between the shaft and the web. In such implementations the exercise device further includes an encoder supported by the web and rotationally coupled to the cable pulley to measure rotation of the cable pulley. 
     In other implementations the motor is a brushless direct current (BLDC) motor and the exercise device further includes a controller to actuate the motor using trapezoidal commutation. 
     Yet another aspect of the present disclosure is directed to an exercise device including a housing having a top portion and a bottom portion and an internal frame disposed within the housing. The internal frame includes a web extending between the top portion and the bottom portion and a support member offset from the web. The exercise device further includes a dampening block coupled to the web, a bracket coupled to and extending between each of the dampening block and the support member, and a motor including a motor casing and a shaft with the shaft is rotationally fixed by the dampening block. 
     In certain implementations the motor is a brushless direct current (BLDC) motor and the exercise device further includes a motor controller to actuate the motor using trapezoidal commutation. 
     In other implementations the dampening block includes a block defining a channel and the shaft extends through the channel. The dampening block further includes a cover plate abutting the block with the cover plate rotationally fixing the shaft, a first dampening pad disposed between and abutting each of the cover plate and the web, and a second dampening pad disposed between and abutting each of the cover plate and the bracket. 
     In other implementations the top portion includes an aperture and the exercise device further includes a cable pulley coupled to the motor casing, a cable coupled to the cable pulley, and a fairing disposed in the aperture. In such implementations, the cable is routed through the aperture and selectively retractable through the aperture by actuating the motor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The referenced figures of the drawings illustrate various example embodiments of this disclosure. The embodiments and figures described in this disclosure are to be considered illustrative rather than limiting. 
         FIG.  1    is a first isometric view of an exercise device according to the present disclosure. 
         FIG.  2    is a second isometric view of the exercise device of  FIG.  1    with a housing partially removed to illustrate internal components of the exercise device. 
         FIG.  3    is a diagram of an operating environment including the exercise device of  FIG.  1    in which functions of the exercise device are supported by a user computing device and a remote fitness platform. 
         FIG.  4    is an elevation view of a web assembly of the exercise device of  FIG.  1   . 
         FIG.  5    is a first isometric view of the web assembly of  FIG.  4   . 
         FIG.  6    is a second isometric view of the web assembly of  FIG.  4   . 
         FIG.  7    is a partially exploded view of the web assembly of  FIG.  4   . 
         FIG.  8    is an exploded view of a dampening block of the web assembly of  FIG.  4   . 
         FIG.  9    is a partial cross-sectional view of the dampening block of  FIG.  8    as assembled in the web assembly of  FIG.  4   . 
         FIG.  10    is a partial isometric view of internal components of the exercise device of  FIG.  1    illustrating an example placement of a support bracket coupled to the dampening block. 
         FIG.  11    is a partial isometric view of the web assembly of  FIG.  4    illustrating an encoder and encoder coupling. 
     
    
    
     DETAILED DESCRIPTION 
     Aspects of this disclosure include exercise devices for use in performing various resistance-based exercises. The exercise devices include a housing having a top portion through which a motor-driven cable extends. In certain implementations, the housing may have a form factor similar to that of a fitness step/step platform, a plyometric box, or other similar fitness equipment; however, and more generally, the housing may have any suitable prismatic shape that facilitates the various use cases discussed in this disclosure. A user can equip the end of the cable with a grip, collar, belt, or similar component to facilitate performance of different exercises. During operation, the motor supplies resistance by counteracting extension of the cable by the user and/or controllably retracting the cable against the user. The exercise device may include or be in communication with computing elements configured to control the motor, measure user performance, monitor system behaviors, and perform other similar functions. 
     The motor replaces weights, bands, and other resistance elements found in conventional exercise equipment. The motor may provide a controllable resistance force, which may be a constant resistance force and retraction rate. However, the motor can also be actively controlled to provide greater variety and flexibility as compared to conventional resistance sources (e.g., weights, bands, etc.). For example, and among other things, the exercise device may control the motor to supply resistance that automatically varies over a given range of motion (e.g., applying a different resistance during the concentric versus eccentric phase of an exercise or varying in response to some user feedback parameter such as extraction rate) or provides a constant resistance that eliminates inertial effects common with conventional resistance elements. 
     The exercise device may include or be communicably coupled to various devices for controlling the exercise device and providing feedback to a user. For example, the exercise device may connect to and communicate with a computing device, such as a smartphone, tablet, laptop, smart television, etc., to enable the user to select a workout and/or exercise, adjust exercise parameters (e.g., a range of motion of the exercise, a speed of the exercise, a load, or any other similar parameter), view historical performance data, and the like. In certain implementations, such computing devices may also facilitate streaming of video or other multimedia content (e.g., classes) to guide a user&#39;s exercise or to facilitate participation in streaming or real-time interactive classes and competitions. In still other implementations, the exercise platform may be used in conjunction with a gaming platform or other computing device capable of running games or similar interactive software. The exercise device may also receive control instructions from such computing devices. 
     Exercise devices of this disclosure may also connect to and communicate with each other or to other computing devices over a network, which may include the Internet, local networks, and combinations thereof. In one implementation, a cloud-based platform may interact with exercise devices of this disclosure and associated user computing devices (e.g., a user&#39;s smartphone) to distribute resistance profiles (which may include control instructions) for exercises, store and update user information including information representative of a user performing an exercise, and present tracking information to users and personnel such as gym facility managers, personal trainers, physiotherapists, and others who may be working with a user. The cloud-based computing platform further enables the generation, updating, and storage of content for use with the exercise device including, but not limited to, resistance profiles, workout plans, multimedia content, and the like. 
       FIG.  1    is an isometric view of an exercise platform  100  according to one implementation of the present disclosure.  FIG.  2    is an isometric view of exercise platform  100  with a housing  102  and other external components removed to illustrate various internal components of the exercise platform  100 . Referring to  FIG.  1   , exercise platform  100  includes a housing  102  having a top portion  104  through which a cable  106  passes. In certain implementations, top portion  104  includes an aperture  120  within which a fairing  122  or similar guide element is disposed to permit multi-directional retraction and extension of cable  106 . As shown, cable  106  may end in a handle  108 ; however, in other implementations, cable  106  ends in a strap, grip, belt, rope loop, or similar component to facilitate performance of different exercises. More generally, the cable may be coupled with any suitable attachment to facilitate various possible exercises. Handle  108  may be permanently fixed to cable  106  or may be removable such that handle  108  may be swapped with one or more alternative attachments to facilitate different exercises. For example, as shown in  FIG.  1   , handle  108  couples to cable  106  by a carabiner  107 . Carabiner  107  is just one example of a structure for easily coupling handle  108  to cable  106  and this disclosure contemplates that any suitable coupling mechanism may be used to join handle  108  to cable  106 . During performance of an exercise, a user extends cable  106  and/or resists retraction of cable  106  with resistance provided by a motor  110  (shown in  FIG.  2   ) disposed within housing  102  and coupled to cable  106 , e.g., by a cable pulley  112  (also shown in  FIG.  2   ) coaxially mounted to motor  110 , and about which the cable is spooled and unspooled during operation. In certain implementations, cable pulley  112  may be a separate component coupled to a rotating component (e.g., an axle or rotating casing) of motor  110 . Alternatively, cable pulley  112  may be integrally formed with the rotating component of motor  110 . 
     Exercise platform  100  may include a control system (including, e.g., a motor controller, a motor drive, a microprocessor, and/or other related components) for actuating/controlling motor  110  and the resistance provided by motor  110 . Exercise platform  100  may further include various sensors for providing feedback to the control system to facilitate control of motor  110 . For example, in certain implementations, exercise platform  100  may include one or more of a current sensor, a position sensor (e.g., an encoder), an accelerometer, or another sensor for measuring parameters related to motor activity and which can be used in the control and operation of motor  110 . In certain implementations, force sensors (e.g., load cells, strain gauges, etc.) incorporated into exercise platform  100  may also supply feedback for controlling motor  110 , assessing user performance, energizing the exercise device, providing information to the exercise device or other systems, and other similar functions. 
     Motor  110  and the associated motor control components may provide a variety of different resistance profiles depending on the exercise being performed, settings provided by the user, a workout plan of the user, and the like. In one mode of operation, motor  110  may provide constant resistance over a complete range of motion for an exercise. As another example, motor  110  may provide a first resistance during a first phase of an exercise (e.g., a concentric phase of the exercise) and a second, different, resistance during a second phase of the exercise (e.g., an eccentric phase of the exercise). As yet another example, motor  110  may vary resistance over any or all phases of an exercise. In at least certain implementations, the system may provide controls (e.g., through a user interface provided on a smart phone or tablet) to set a starting point for an exercise, which may correspond to an amount of retraction (unspooling) of the cable above which the resistance force is applied and below which a nominal retraction force is applied. 
     By way of example, a user of exercise platform  100  may perform a squat motion while holding handle  108  in front of his or her body and standing on top portion  104 . In one example, motor  110  may supply constant resistance (e.g., 100 lbs. of resistance) during both the eccentric (descending) and concentric (ascending) phases of the squat. In another example, motor  110  may supply a first resistance (e.g., 50 lbs. of resistance) during the eccentric phase of the squat but subsequently increase resistance (e.g., to 100 lbs.) during the concentric phase of the squat, thereby emphasizing the concentric phase. In yet another example, motor  110  may supply relatively low resistance when the user is at depth but supply increased resistance as the user reaches an upright position. Among other things, such varying of resistance may encourage a full and safe range of motion by reducing load in typically problematic points of the exercise. As a final and additional non-limiting example, motor  110  may supply a random or otherwise dynamically varying resistance (e.g., a “noisy” load that ranges from 40 lbs. to 60 lbs.) over some or all of the squat motion, thereby forcing the user to recruit a broader range of stabilizing muscles than if a constant resistance were to be applied by motor  110 . 
     As illustrated in  FIG.  1   , exercise platform  100  may include various other features. For example, housing  102  may include a grip  124  or similar feature to facilitate transportation of exercise platform  100 . Exercise platform  100  may also include an electronics panel  126 . Among other things, electronics panel  126  may include one or more ports to facilitate communication between exercise platform  100  and other computing devices, a display (e.g., an LED or LCD screen) for providing information to a user, one or more lights to indicate status or operation of exercise platform  100  (e.g., an “ON/OFF” light indicator), one or more switches (e.g., a power switch), and the like. In at least certain implementations, exercise platform  100  may include a battery such that exercise platform  100  may be optionally operated without being plugged into a wall outlet or other external power source. In such cases, exercise platform  100  may further include a charging port or similar plug (not illustrated) to facilitate charging of the battery or otherwise powering exercise platform  100 . 
     Referring to  FIG.  2   , an isometric view of exercise platform  100  is provided with portions of housing  102  removed for clarity and to reveal internal components of exercise platform  100 . As previously discussed, exercise platform  100  includes motor  110 , which may be coupled to and drive a cable pulley  112  to control retraction and extension of cable  106 . Exercise platform  100  includes an internal frame  114  that provides structural integrity to exercise platform  100  and structure for coupling to and supporting internal components of exercise platform  100 . As illustrated, internal frame  114  includes a web  116  extending transversely through housing  102 . In at least certain implementations, motor  110  is coupled to and supported by web  116  such that cable pulley  112  aligns with aperture  120  of top portion  104 . Internal frame  114  may include additional elements to provide additional structural integrity and/or mounting locations for other components of exercise platform  100 . For example, internal frame  114  may include one or more transverse members (such as transverse member  118 ), which extends parallel to but offset from web  116 . 
       FIG.  3    illustrates an example operating environment  300  including exercise platform  100 . In at least certain implementations, exercise platform  100  communicates with one or more external computing devices, such as computing device  302 . Although illustrated as a smartphone, computing device  302  may be any suitable computing device capable of connecting to and communicating with a communication module or similar communication component of exercise platform  100  through a wired or wireless connection. 
     Computing device  302  may execute an application for interfacing with and controlling exercise platform  100 . For example, the application executed on computing device  302  may permit a user of computing device  302  to change a resistance of exercise platform  100  or a resistance profile executed by exercise platform  100 . In other implementations, the application may allow the user to select an exercise or workout routine the automatically reconfigures exercise platform  100  as the user progresses through the exercise or workout routine. During operation, exercise platform  100  may transmit data, such as position data for cable  106 , such that the application may track successful completion of exercises and workout routines by the user. 
     One or both of exercise platform  100  and computing device  302  may further communicate with a fitness platform  304  over a network  306 , such as the Internet. Among other things, fitness platform  304  may provide a portal, website, application, etc. through which a user of computing device  302  may access information and content related to use of exercise platform  100 . For example, fitness platform  304  may include a repository or similar source of video, text, or other content directed to use of exercise platform  100 , performing certain exercises, and/or fitness and exercise more generally. As another example, fitness platform  304  may support user accounts such that a user of computing device  302  and exercise platform  100  may track his or her historic performance and improvement, create and track workouts and fitness plans, participate in leaderboards and other community-related features, and the like. In at least certain implementations, fitness platform  304  may facilitate real-time classes, competitions, and similar group activities that simultaneously support multiple users of exercise devices. For example, in the context of a class, a live streamed video of an instructor may be provided by fitness platform  304  to multiple users and each exercise device (or a related/connected computing device) may in turn provide exercise data (e.g., resistance level, speed, rep completion, etc.) for maintaining and populating a class leaderboard or similar display of participant performance. 
     As noted above, implementations of exercise devices according to this disclosure rely on an electric motor to supply resistance during exercises performed by a user. Although electric motors can be cost effective, energy efficient, and highly controllable, many types of electric motors and motor-driven systems can be susceptible to vibration. From a device life perspective, excessive vibration can result in increased wear of components and loosening of fasteners, joints, etc., among other things. Vibration can also be a substantial source of noise during operation of a motor-driven device and, as a result, can have a significant impact on the usability and user experience of a device. 
     In the context of motor-driven exercise equipment, vibration and resulting noise can affect the user&#39;s enjoyment of and engagement with the equipment and can also dictate when and where a user may exercise with the equipment. For example, excessive vibration or noise may preclude use of the equipment due to concerns and complaints from neighbors or others living with the user. Even if not fully precluded, noise may nevertheless limit a user from exercising early in the morning or later in the evening when noise may be disruptive to others that live with the user. As another example, excessive noise may preclude use of certain equipment in a group or class setting where the din resulting from multiple pieces of equipment operating simultaneously may drown out an instructor or rise to the level of causing discomfort or hearing damage to class participants. 
     At least some vibration may result from mechanical considerations (e.g., motor imbalances, misalignment of components, etc.). Other sources of vibration may be the result of the specific type of motor and/or commutation method used. For example, brushless direct current (BLDC) motors are a cost-effective and easily controlled option for many electric motor applications and may be controlled using trapezoidal commutation (which is also referred to as “six-step commutation”). However, trapezoidal commutation is inherently noisy due to torque and cogging ripple. Such noise can be particularly noticeable and problematic at slower rotational speeds. Although tuning of the motor and commutation scheme may be used to reduce at least some vibration and noise, such tuning may be insufficient to reduce noise to a desirable level. 
     Considering the foregoing, the present disclosure includes structural improvements to motor-driven exercise devices for reducing vibration and corresponding noise. In one aspect of this disclosure, a specially designed dampening block supports the motor of the exercise device from an internal web of the exercise device. Specifically, the dampening block couples to a shaft of the motor to prevent rotation of the motor and has a layered construction including multiple dampening pads for attenuating vibration of the motor during operation. The dampening block further couples to an internal web of the exercise device such that the motor is cantilevered from the dampening block. In certain implementations, a reinforcing bracket extending from the dampening block to an internal frame of the exercise device supplies further support and dampening of motor vibrations. 
       FIGS.  4 - 7    depict various views of web  116  and components coupled thereto. For convenience, this disclosure collectively refers to the components illustrated in  FIGS.  4 - 7    as a web assembly  400 . Accordingly,  FIG.  4    is an elevation view of web assembly  400 ,  FIG.  5    is a side perspective view of web assembly  400 ,  FIG.  6    is a lower side perspective view of web assembly  400 , and  FIG.  7    is a lower exploded view of web assembly  400 . 
     Referring to  FIGS.  4 - 7   , web assembly  400  includes web  116 , which supports motor  110  within housing  102  (shown in  FIG.  1   ). Web assembly  400  further includes a dampening block  402  that couples motor  110  to web  116  and a bracket  408  coupled to dampening block  402  and extending to transverse member  118  of internal frame  114  (e.g., as shown in  FIG.  10   ). 
     In certain implementations, motor  110  is a brushless direct current (BLDC) hub motor. In general, a hub motor includes an internal motor assembly (not shown) about which a motor casing  404  rotates. Hub motors can be direct drive or geared. In direct drive hub motors, internal components of the hub motor function as the stator of the motor while the motor casing  404  is configured as the rotor. In contrast, the internal motor assembly of geared hub motors include both a stator and rotor. The rotor of the motor assembly mates with motor casing  404  by an internal gear assembly (e.g., a planetary gear assembly, not shown) such that rotation of the rotor indirectly drives rotation of motor casing  404  using the gears. In either design, the motor includes an externally protruding shaft for mounting the motor to a support structure and that couples to the stator (directly or indirectly). In most applications, mounting rotationally fixes the shaft such that the stator remains stationary during operation of the motor. 
     Web assembly  400  includes web  116  and motor  110  and related structures for coupling motor  110  to web  116 . As illustrated, motor casing  404  of motor  110  may be coupled to cable pulley  112  such that rotation of motor casing  404  rotates cable pulley  112 . Cable pulley  112  is further illustrated as being coupled to an encoder  450  configured to measure rotational position of cable pulley  112  and motor casing  404  during operation of exercise platform  100 . Web  116  may further support fairing  122  in alignment with cable pulley  112  to guide a cable (not shown) spooled about cable pulley  112  outside of housing  102 . 
     Dampening block  402  couples motor  110  to web  116 . More specifically, dampening block  402  couples to web  116  and receives and rotationally fixes a shaft  406  of motor  110 . As a result, motor  110  is cantilevered from dampening block  402  within housing  102  of exercise platform  100 . To accommodate motor  110 , cable pulley  112 , encoder  450 , and other internal components of exercise platform  100 , web  116  may include one or more cutouts such as cutout  410  (shown in  FIG.  4   ) within which those components may be at least partially disposed. 
       FIG.  8    is an exploded view of dampening block  402 . In at least certain implementations, dampening block  402  may include a shaft coupling assembly  502  including a primary block  504  and a cover plate  506 . Each of primary block  504  and cover plate  506  may be formed of a relatively rigid and solid material such as, without limitation, steel or aluminum. Dampening block  402  may further include various dampening pads. For example, as shown in  FIG.  8   , dampening block  402  includes a dampening pad  508  such that when dampening block  402  is assembled into web assembly  400 , dampening pad  508  is positioned between primary block  504  and bracket  408 . Dampening block  402  may further include a dampening pad  510  such that when dampening block  402  is assembled into web assembly  400 , dampening pad  510  is positioned between cover plate  506  and web  116 . In contrast to primary block  504  and cover plate  506 , dampening pad  508  and dampening pad  510  may be formed from a suitable elastomeric material selected to absorb and dampen vibrations transmitted to shaft coupling assembly  502  by shaft  406 . In certain implementations, one or both of dampening pad  508  and dampening pad  510  may have a layered construction of multiple materials or instead be replaced by multiple and separate dampening pads. In implementations in which bracket  408  is omitted, dampening pad  508  may be omitted from dampening block  402 . 
     Primary block  504  may include a channel  512  that receives shaft  406  of motor  110  during assembly of web assembly  400 . Cover plate  506  may also include a slot  514  or similar feature configured to fix rotation of shaft  406 . In certain implementations and depending on the dimensions of shaft  406  and cover plate  506 , dampening pad  510  may also include a slot  516  into which a portion of shaft  406  extends to rotationally fix shaft  406 . 
     Coupling and fixation of shaft  406  by dampening block  402  is further illustrated in  FIG.  9   , which is a partial cross-sectional view of web assembly  400 .  FIG.  9    includes motor  110  from which shaft  406  extends. As shown, shaft  406  extends into dampening block  402  such that dampening block  402  supports shaft  406 . Specifically, shaft  406  extends through channel  512  of primary block  504 . 
     Although shaft  406  may be coupled to and retained by dampening block  402  in various ways, in at least certain implementations, shaft  406  may include a flat  507  such that a portion  509  distal flat  507  protrudes radially. In such implementations, when shaft  406  and dampening block  402  are assembled together, flat  507  may be positioned to abut cover plate  506  such that portion  509  extends into slot  514  and slot  516 . In such a configuration, each of flat  507 , slot  514 , and slot  516  collectively provide both longitudinal and rotational constraints for shaft  406 , thereby coupling motor  110  to dampening block  402  and web  116 . 
     As previously noted, bracket  408  may provide additional support and dampening of motor  110 . As shown in  FIGS.  4 - 7   , bracket  408  is coupled to dampening block  402  and extends from dampening block  402 . Referring to  FIG.  10   , in at least certain implementations bracket  408  may extend from dampening block  402  to transverse member  118  of internal frame  114 . As illustrated in both  FIGS.  2  and  10   , transverse member  118  may extend through housing  102  parallel to web  116  and below top portion  104 . In at least certain implementations, a dampening pad or similar insert (not shown) may be disposed between bracket  408  and transverse member  118  to provide additional dampening and noise reduction. 
     Although  FIG.  10    illustrates bracket  408  extending to transverse member  118 , this disclosure contemplates that bracket  408  may extend to any substantially fixed element of exercise platform  100  and, in particular, other elements of internal frame  114 . So, for example, while  FIGS.  2  and  10    illustrate bracket  408  as extending in an upwardly slanted direction to couple with transverse member  118  below top portion  104 , bracket  408  may alternatively extend in a downwardly slanted direction to couple bracket  408  to a similar member or structural element disposed adjacent a bottom portion of housing  102 . More generally, bracket  408  may be configured to extend between dampening block  402  and any suitable fixed location or structure within housing  102 . 
     During operation of motor  110 , shaft  406  transmits resulting vibrations of motor  110  to dampening block  402 , which in turn transmits the vibrations to internal frame  114 . More specifically, dampening block  402  transmits at least a portion of the vibrational energy to web  116  due to the coupling of dampening block  402  to web  116 . Notably, dampening pad  510  (disposed between shaft coupling assembly  502  of dampening block  402  and web  116 ) dampens at least a portion of the vibrational energy transmitted from dampening block  402  to web  116 . In implementations including bracket  408 , an additional portion of the vibrational energy is transmitted from dampening block  402  to transverse member  118  (or a similar component of internal frame  114 ) due to the coupling of bracket  408  to both dampening block  402  and transverse member  118 . Dampening pad  508  (disposed between shaft coupling assembly  502  and bracket  408 ) dampens at least a portion of the vibrational energy transmitted from dampening block  402  to bracket  408 . 
     In addition to dampening pad  508  and dampening pad  510 , additional dampening and acoustic cancelation may be provided by various structural elements of exercise platform  100 . For example, and without limitation, one or more of web  116 , bracket  408 , and transverse member  118  (or other structural member to which bracket  408  couples) may be made of materials or be shaped to dampen vibrations or shift vibration frequencies. Moreover, additional dampening pads or similar dampening components may be disposed between components of exercise platform  100  (e.g., between elements of internal frame  114 ) or between exercise platform  100  and the surrounding environment (e.g., on the underside of housing  102  such that the dampening pads are between exercise platform  100  and the floor) to further dampen vibrations resulting from operation of motor  110 . 
     Each of dampening block  402  and bracket  408  provide substantial dampening of vibration generated by motor  110  during use of exercise platform  100  and a corresponding reduction in noise. Among other things, the reduction enables the use of cost-effective albeit noisier motor types and control schemes. For example, and as noted above, BLDC motors operated using trapezoidal commutation are often considered efficient and cost-effective but ultimately noisy, particularly when operated at low speeds. During testing and development, the dampening techniques and structures disclosed herein substantially reduced vibration such that BLDC motors using trapezoidal commutation were found to be a suitable alternative to more costly but inherently quieter motor configurations. 
     As noted in the context of  FIGS.  4 - 7   , web assembly  400  may further include encoder  450  for measuring rotation of cable pulley  112  and motor  110 .  FIG.  11    is a view of the web assembly of  FIG.  4    illustrating an example arrangement of an encoder and encoder coupling. In at least certain implementations and as illustrated in  FIG.  11   , encoder  450  may be coupled to web  116  using a suitable bracket or support such that a shaft of encoder  450  is aligned with cable pulley  112  and motor  110 . To permit at least some misalignment between encoder  450  and cable pulley  112 /motor  110 , web assembly  400  may include a flexible coupling  452  for coupling the shaft of encoder  450  to cable pulley  112 . For example, flexible coupling  452  may be a double-loop style encoder coupling. Notably, due to flexible coupling  452 , encoder  450  does not provide any substantial load bearing support for motor  110  such that motor  110  remains substantially supported at dampening block  402 . 
     Although various representative embodiments have been described above with a certain degree of particularity, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the spirit or scope of the inventive subject matter set forth in the specification. All directional references (e.g., upper, lower, upward, downward, left, right, leftward, rightward, top, bottom, above, below, vertical, horizontal, clockwise, and counterclockwise) are only used for identification purposes to aid the reader&#39;s understanding of the embodiments of the present invention, and do not create limitations, particularly as to the position, orientation, or use of the invention unless specifically set forth in the claims. Joinder references (e.g., attached, coupled, connected, and the like) are to be construed broadly and may include intermediate members between a connection of elements and relative movement between elements. As such, joinder references do not necessarily infer that two elements are directly connected and in fixed relation to each other. 
     In some instances, components are described with reference to “ends” having a particular characteristic and/or being connected to another part. However, those skilled in the art will recognize that the present invention is not limited to components which terminate immediately beyond their points of connection with other parts. Thus, the term “end” should be interpreted broadly, in a manner that includes areas adjacent, rearward, forward of, or otherwise near the terminus of a particular element, link, component, member, or the like. In methodologies directly or indirectly set forth herein, various steps and operations are described in one possible order of operation, but those skilled in the art will recognize that steps and operations may be rearranged, replaced, or eliminated without necessarily departing from the spirit and scope of the present invention. It is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative only and not limiting. Changes in detail or structure may be made without departing from the spirit of the invention as defined in the appended claims.