Patent Publication Number: US-2023134906-A1

Title: Caster boards with removable insert

Description:
CROSS-REFERENCE 
     This application is a continuation of U.S. patent application Ser. No. 17/025,588, filed Sep. 18, 2020, which claims the priority benefit of U.S. Provisional Patent Application No. 62/902,241, filed Sep. 18, 2019, the entirety of each of which is incorporated by reference herein. Additionally, all applications for which a foreign or domestic priority claim is identified in the Application Data Sheet as filed with the present application are hereby incorporated by reference under 37 CFR 1.57. 
    
    
     BACKGROUND 
     Field of the Disclosure 
     This disclosure relates generally to wheeled vehicles, such as caster boards that include platforms connected by a split neck region having a first section, a second section, and an aperture therebetween. The aperture can removably receive an insert, which can provide additional functionality and/or change the vehicle&#39;s riding characteristics. 
     Description of Certain Related Art 
     Some caster boards are two-wheeled vehicles that includes a deck with two platforms that are connected by torsion bar and/or a neck region of the platform. The neck region and/or torsion bar can function as a torsion element and may be configured to resiliently twist along a longitudinal axis of the vehicle. One or more wheels can be attached to each platform. The wheels can be a caster wheels. A rider can stand on the deck and obtain locomotion by pivoting the front and rear platforms relative to each other with a twisting motion. 
     SUMMARY OF CERTAIN FEATURES 
     In one broad aspect, a caster board assembly is provided, comprising a caster board comprising a front end, a rear end, and a neck between the front end and the rear end, the neck comprising a gap; and an insert configured to be removably positioned in the gap. 
     The insert may be configured to modify a structural property of the caster board. The insert may be configured to alter the torsional stiffness of the caster board. The insert is configured to add mass to the caster board. The insert may be configured to redistribute or control the distribution of mass across the caster board. 
     The gap may include a through-hole extending through the neck. The gap may include a blind hole extending partway through the neck. The gap may include a chamfered section adjacent an upper surface of the caster board. 
     The insert may include an electronic device. The insert may include an image and/or audio capture device. The insert may include a lighting element. The insert may include a security device. The insert may include a mounting device. The insert may include a wireless communication module. The insert may be configured to communicate with a separate device to receive control information and/or to transmit data. The insert may include an adapter configured to provide a secondary aperture with different dimensions than the aperture. 
     In another broad aspect, a caster board is provided, comprising: a platform, the platform comprising: a front platform section; a rear platform section; a first neck section extending between the front platform section and the rear platform section; and a second neck section extending between the front platform section and the rear platform section, the first neck section extending at an oblique angle to the second neck section; a first caster assembly connected to the first platform section; and a second caster assembly connected to the second platform section. 
     The oblique angle may be at least 2°. The oblique angle may be between 2° and 3°. The oblique angle may be between 1° and 5°. The oblique angle may be less than 25°, less than 20°, less than 15°, less than 10°, or less than 5°. 
     The caster board may additionally include an aperture extending through at least a portion of the platform, the aperture located between the first neck section and the second neck section. The aperture may be longitudinally asymmetric. The aperture may be vertically asymmetric. A distance between the first and second neck sections adjacent the rear platform section may be shorter than a distance between the first and second neck sections adjacent the front platform section. 
     The first and second neck sections may be located on opposite sides of a longitudinal axis of the caster board. The platform may be configured to twist about the longitudinal axis of the caster board, and a torsional stiffness of the first and second neck sections may be less than a torsional stiffness of the front platform section and less than a torsional stiffness of the rear platform section. 
     In another broad aspect, a caster board is provided, comprising: a front platform section; a rear platform section; a longitudinally tapering neck section extending between the front platform section and the rear platform section, a portion of the longitudinally tapering neck section adjacent the front platform section being wider than a portion of the longitudinally tapering neck section adjacent the rear platform section; and an aperture extending through at least a portion of the longitudinally tapering neck section. 
     The neck section may include two substantially linear neck portions extending on either side of the aperture. The portions of the substantially linear neck portions extending adjacent the aperture may have a substantially constant upper profile along their length. 
     The caster board may further include an insert retained within the aperture. The aperture may include a chamfered section and the insert may include a flared cross-sectional shape. The insert may be configured to increase a torsional stiffness of the longitudinally tapering neck section. The insert may include an electronic device configured to record at least one of video, images, or audio. 
     A width of the aperture may increase with increasing distance from the rear platform section. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other features of the present disclosure will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only several embodiments in accordance with the disclosure and are not to be considered limiting of its scope, the disclosure will be described with additional specificity and detail through use of the accompanying drawings. In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. 
         FIG.  1    is a side perspective view of an embodiment of a caster board having including a split neck region and an aperture, showing the caster board from the side and above. 
         FIG.  2    is a front side perspective view of the caster board of  FIG.  1   , seen from the front, side and above. 
         FIG.  3    is a top plan view of the caster board of  FIG.  1   . 
         FIG.  4    is a bottom plan view of the caster board of  FIG.  1   . 
         FIG.  5    is a right side view of the caster board of  FIG.  1   ; the left side view being a mirror image thereof. 
         FIG.  6    is a front view of the caster board of  FIG.  1   . 
         FIG.  7    is a rear view of the caster board of  FIG.  1   . 
         FIG.  8    is a rear side perspective view of the caster board of  FIG.  1   , seen from the back, side and below. 
         FIG.  9    is a cross-sectional view of the caster board of  FIG.  1   , taken along the line A-A of  FIG.  4   . 
         FIG.  10    is a detail cross-sectional view of a portion of the caster board of  FIG.  1   . 
         FIGS.  11 A to  11 E  schematically illustrate an embodiment of a caster board under various loading conditions and the resulting positions of the caster assemblies. 
         FIG.  12    illustrates a plot of relative twist angle along the length of a platform in response to an applied torque. 
         FIG.  13    is an exploded view of a caster board and an insert dimensioned to fit within the aperture in the caster board. 
         FIG.  14    is a flow diagram illustrating an exemplary process for modifying a structural property of a caster board using an insert. 
     
    
    
     DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS 
       FIG.  1    is a side perspective view of an embodiment of a caster board, showing the caster board from the side and above.  FIG.  2    is a front side perspective view of the caster board of  FIG.  1   , seen from the front, side and above.  FIG.  3    is a top plan view of the caster board of  FIG.  1   .  FIG.  4    is a bottom plan view of the caster board of  FIG.  1   .  FIG.  5    is a side view of the caster board of  FIG.  1   .  FIG.  6    is a front view of the caster board of  FIG.  1   .  FIG.  7    is a rear view of the caster board of  FIG.  1   .  FIG.  8    is a rear side perspective view of the caster board of  FIG.  1   , seen from the back, side and below.  FIG.  9    is a cross-sectional view of the caster board of  FIG.  1   , taken along the line A-A of  FIG.  4   .  FIG.  10    is a detail cross-sectional view of a rear of the caster board of  FIG.  1   . 
     As can be seen in  FIG.  1   , the caster board  100  includes a front region  102 , a rear region  104 , and a neck region  106  extending between the front region  102  and the rear region  104 . The front and rear regions  102 ,  104  can form a deck or platform  110 , which can support and/or receive the feet of a user. In the illustrated embodiment, the front region  102  includes a front platform section  112  of the deck or platform  110 , and an underlying front caster assembly  130   a . The rear region  104  includes a rear platform section  114  of the platform  110 , and an underlying rear caster assembly  130   b . The neck region  106  includes a first neck section  116   a  and a second neck section  116   b  extending between the front platform section  112  and the rear platform section  114  of the platform  110 . As illustrated, in some embodiments, the first and second neck sections  116   a ,  116   b  (also called first and second neck portions) can be positioned on either side of an aperture  160  extending into and/or through the platform  110 . The aperture  160  can comprise a through-hole, blind hole, groove, recess, notch, or otherwise. In some implementations, one or more of the neck sections  116   a ,  116   b  provides a handle for carrying the board  100 . 
     In the illustrated embodiment, the platform  110  is a single piece, such as a piece which may be molded or otherwise integrally formed into a desired shape. In some embodiments, the platform  110  may comprise a plastic material, or any other suitable material which may be resiliently twisted during operation of the caster board, as discussed in greater detail herein. In some implementations, the platform  110  is not comprised of and/or assembled from discrete front and rear sections that are connected by a discrete neck and/or torsion bar. 
     A lateral width of the front platform section  112  and a lateral width of the rear platform section  114  may be greater than a lateral width between the outer edge  126   a  of first neck section  116   a  and outer edge  126   b  of second neck section  116   b  in the neck section  106  of the caster board  100 . The width of the front platform section  112  and the rear platform section  114  allow these sections to support a respective foot of a rider during operation of the caster board  100 . In some variants, the increased width of the front platform section  112  and the rear platform section  114  allows these sections to resist twisting and/or to concentrate the twisting of the platform  110  within the neck region  106  of the caster board  100 , as discussed in greater detail herein. 
     In the illustrated embodiment, such as can be seen in  FIG.  3   , the front platform section  112  includes a front edge  120   a , which in the illustrated embodiment is somewhat convex. There can be a distinct rounded transition between the front edge  120   a  and side edges  122   a  and  122   b  of the front platform section  112 , which are generally linear with a slight convex curvature, and taper slightly outward with increased distance from the front edge  120   a . Rearward of the side edges  122   a  and  122   b , there is another distinct rounded transition between the side edges  122   a  and  122   b  to the inwardly tapering inboard sides  124   a  and  124   b  of the inboard portion of the front platform section  112 . The inboard sides  124   a  and  124   b  are separated from the outer edge  126   a  of first neck section  116   a  and outer edge  126   b  of second neck section  116   b  by additional distinct rounded transitions. 
     In some embodiments, the rear platform section  114  is similar to the front platform section  112 . As shown, in some variants, the rear edge  120   b  of the platform  110  has a slightly concave shape. The side edges  122   c  and  122   d  of the rear platform section  114  can be generally linear, have a slight convex curvature, and/or taper slightly outward with increased distance from the rear edge  120   b . Forward of the side edges, the inwardly tapering inboard sides  124   c  and  124   d  of the rear platform section  114  taper respectively to the outer edge  126   a  of first neck section  116   a  and the outer edge  126   b  of second neck section  116   b    
     In some embodiments, the front and rear platform sections  112  and  114  may have shapes which are more or less angular than the illustrated embodiment. In some embodiments, one or both of the front and rear platform sections  112  and  114  may include one or more curvilinear edges in place of two or more of the adjacent edges depicted herein. In addition, the transition between the front and rear platform sections  112  and  114  and the first and second neck sections  116   a  and  116   b  may not include a discrete rounded transition. Instead, a single curvilinear edge may extend along at least a portion of one of the first and second neck sections  116   a  and  116   b  and at least one of the front and rear platform sections  112  and  114 . 
     The upper surface  118  of the platform  110  is not planar in the illustrated embodiment but includes a central recessed portion  170  that extends from the front platform section  112  to the rear platform section  114 , with a raised lip  172  surrounding it. The peak of the raised lip  172  is recessed from some or all of the edges of the platform  110 , with an outer portion  174  extending downward to a sidewall of adjacent edge of the platform  110 . The outer portion  174  may include a bevel, chamfer, or fillet. At least a portion of the sidewalls at the edges of the board may be substantially vertical. The height of the sidewall may vary across the length of the board. For example, in the illustrated embodiment, the height of the sidewall within the neck region  106  may be comparatively greater than the height of the sidewall in the front and rear regions  102  and  104  of the board  106 . 
     In the illustrated embodiment, the first and second neck portions  116   a  and  116   b  have a substantially constant thickness across some or most of their lengths. The first and second neck portions  116   a ,  116   b  can be oriented at a slight acute angle to the longitudinal axis  108  of the caster board  100 . In particular, the first and second neck portions  116   a  and  116   b  are oriented along respective longitudinal axes which converge at a point rearward of the neck portion  106 . In some implementations, the acute angle is less than or equal to about: 25°, 20°, 15°, 10°, 5°, 4°, 3°, 2°, 1° or otherwise. In the particular embodiment illustrates in  FIGS.  1  to  10   , the convergence point of these axes may be rearward of the back edge  120   b  of the board  100 . Certain embodiments may include different orientations of the first and second neck portions  116   a  and  116   b  relative to one another. In some embodiments, the first and second neck portions  116   a  and  116   b  may be oriented generally parallel to one another, and parallel to the longitudinal axis  108  of the caster board  100 . 
     As mentioned above, the caster board  100  can comprise an aperture  160  (e.g., a through-hole), which can be located between the first and second neck portions  116   a  and  116   b . In some embodiments, the aperture  160  can is centrally located, such as at about the midpoint of: the longitudinal length of the caster board  100 , the lateral width of the caster board  100 , and/or the longitudinal length of the neck portions  116   a  and  116   b . The generally longitudinally extending sidewalls  162   a  and  162   b  of the aperture  160  are bounded by the interior sides of the first and second neck portions  116   a  and  116   b . The orientation of the first and second neck portions  116   a  and  116   b  can be at a non-zero angle to one another, as shown in  FIGS.  3  and  4   . In some implementations, because of this non-zero angle and the generally constant thickness of the first and second neck portions  116   a  and  116   b , the aperture  160  has a generally trapezoidal shape, having a thicker width closer to the front sidewall  164   a  of the aperture  160 , and having a thinner width closer to the rear sidewall  164   b  of the aperture  160 . In some embodiments, the aperture  160  tapers vertically, such as being wider at a top (e.g., flush with the top of the platform  110 ) and narrower at the bottom of the aperture  160 . This longitudinally and/or vertically asymmetrical shape can compel a particular orientation of an object or objects dimensioned to be inserted into the aperture  160 , as discussed in greater detail elsewhere herein. In some embodiments, the tapered shape of the aperture  160  aids in receiving and/or securing an insert in the aperture  160 , as is discussed in more detail below. 
     The aperture  160  can include a chamfered upper portion  168  extending around the upper perimeter of the aperture  160 . In the illustrated embodiment, the chamfered upper portion  168  is oriented at larger angles to the surrounding upper surface  118  of the platform  110  than the angles at which the chamfered upper portion  168  is oriented to the sidewalls  162   a ,  162   b ,  164   a , and  164   b  of the aperture  160 . The sections of the chamfered upper portion  168  located forward and rearward of the aperture  160  may be oriented at a shallower slope than the sections of the chamfered upper portion  168  located to the sides of the aperture  160 . As discussed in greater detail elsewhere herein, the chamfered upper portion  168  can facilitate retention of an object or objects dimensioned to be inserted into the aperture  160 . 
     The platform  110  of the caster board  100  is supported by a pair of longitudinally aligned caster assemblies  130   a  and  130   b . Each of the caster assemblies  130   a  and  130   b  includes a king bolt  142  used to mount the caster assemblies  130   a  and  130   b  to the underside of the platform  110 . In particular, the king bolts  142  are inserted through an aperture in angled mounting surfaces  178   a  and  178   b  oriented at an oblique angle to the platform  110 . In the illustrated embodiment, the angled mounting surfaces  178   a  and  178   b  are part of wedge-shaped depressions  176   a  and  176   b  in the platform  110 . In some embodiments, the angled mounting surfaces  178   a  and  178   b  may be defined by an intermediate structure which is secured to the platform  110 . The depressions  176   a  and  176   b  may be hidden and/or covered with cover plates (not shown). The cover plates can be received in and/or connected to the depressions  176   a  and  176   b . The cover plates can be generally flush with a top of the platform  110  and/or can obscure from sight the presence of the depressions  176   a  and  176   b.    
     In the illustrated embodiment, angled mounting surfaces  178   a  and  178   b  are parallel to one another, such that the king bolts  142  of the caster assemblies  130   a  and  130   b  are installed along parallel axes which intersect the longitudinal axis  108  of the caster board  100 . The axes of the king bolts  142  intersect the longitudinal axis at an oblique angle. In some embodiments, this oblique angle is less than 45 degrees, and in some particular embodiments, this oblique angle is roughly 30 degrees. The angle at which the king bolts  142  is installed is a function of the angle of the angled mounting surfaces  178   a  and  178   b , which in turn is a function of the geometry of the wedge-shaped depressions  176   a  and  176   b  in the platform  110 . 
     The king bolts  142  of the caster assemblies  130   a  and  130   b  support caster yokes or forks  140 , the arms of which extend on either side of the wheels  132  to support the wheel pin or axle  134  extending therebetween. The caster assemblies  130   a  and  130   b  may be rotatable 360 degrees about the king bolts  142 . In some embodiments, the range of rotation of the caster assemblies may be constrained to inhibit rotation beyond a certain range. 
     This rotation may be facilitated through the use of one or more bearings. In the illustrated embodiment, each of the caster assemblies  130   a  and  130   b  include a thrust bearing  144  disposed between the crossbar of the fork  140  and the angled mounting surface  178   a  or  178 , and a radial bearing  146  disposed between the crossbar of the fork  140  and the head of the king bolt  142 , between the arms of the fork  140 . The use of one or more suitable bearings allows rotation of the caster assemblies  130   a  and  130   b  even when the caster assembles  130   a  and  130   b  are under the load of a rider operating the caster board  100 . 
     In the illustrated embodiment, the head of the king bolt  142  is located adjacent the wheel  132 , and a nut  148  on the opposite side of the angled mounting surface  178   a  or  178   b  is used to retain the king bolt  142  in place. In some embodiments the orientation of the king bolt  142  and nut  148  may be reversed. In some embodiments, other suitable king pin structures other than a threaded nut and bolt may be used to retain the caster assemblies  130   a  and  130   b  in place. 
     The forks  140  of the caster assemblies  130   a  and  130   b  support the wheel  132  in an offset position, in which the axis of the king bolt  142  does not intersect the wheel axle  134 . Instead, the wheel axle  132  is radially offset from the axis of the king bolt  142 . Rotation of the caster assemblies  130   a  and  130   b  sweeps the wheel  132 , and particular the contact point of the wheel  132  with an underlying surface, out of a plane defined by the axis of the king bolt  142  and the longitudinal axis of the caster board. The offset of the fork  140  will affect the swivel radius of the caster assembly, with an increase in the offset corresponding to an increase in the swivel radius. In the illustrated embodiment, the offset of the fork  140  is greater than the radius of the wheel  132 , such that the axis of the king bolt  142  will not intersect the wheel  132 . 
     In some embodiments, the caster assemblies  130   a  and  130   b  may be self-centering and may be biased to return to a position in which the wheel  132  is aligned with the longitudinal axis of the caster board  100 . In some embodiments, the caster assemblies  130   a  and  130   b  may include a self-centering mechanism such as a coil spring torsion spring (not shown), configured to exert a restoring force on the caster assembly  130   a  or caster assembly  130   b  when the caster assembly rotates such that the wheel  132  is oriented at an oblique angle to the longitudinal axis  108  of the caster board  100 . In some embodiments, the self-centering mechanism may be external to the caster assembly, connected between a portion of the platform  100  and a portion of the caster assembly  130   a  or  130   b . In some embodiments, the self-centering mechanism may be at least partially internal to the caster assembly, such as through the use of an internal torsion spring. 
     The underside of the platform  110  includes a plurality of ribs which provide support for the upper surface of the platform  110 , allowing the platform to bear the weight of a rider. The plurality of ribs, in conjunction with the overall shape and dimensions of the board and the material or materials comprising the board, also affect the resistance of the board to twisting, as discussed in greater detail herein. 
     In the illustrated embodiment, a plurality of generally laterally extending ribs  154  extending from the sidewalls on one side of the platform  110  to the sidewalls on the other side of the platform  110 , except where they intersect the aperture  160  or the wedge-shaped depressions  176   a  and  176   b  in the platform  110 . As can be seen in  FIGS.  6  and  7   , the height of these sidewalls may increase near the longitudinal axis  108  but be thinner near the outer sidewalls of the platform  110 . Such an arrangement may provide clearance for the platform  110  when it is a canted position with one side closer to the ground. The laterally extending ribs  154  are not linear in the illustrate embodiment, but instead have a curved shape, with the center of curvature of each laterally extending ribs  154  located rearward of that rib. The curvatures of the laterally extending ribs  154  may be similar to each other and may in some embodiments be similar to the curvature of the front edge  120   a  and/or the rear edge  120   b . The longitudinal spacing between the laterally extending ribs  154  may vary over the length of the platform  110 , with the spacing between the laterally extending ribs  154  being greater within the first and second neck sections  116   a  and  116   b.    
     In addition, the platform  110  may include a plurality of generally longitudinally extending ribs. A central longitudinally extending rib  150  extends along a longitudinal axis of the board from the frontmost laterally extending rib  154  to the rearmost laterally extending rib  154 , except where it intersects the aperture  160  and the wedge-shaped depressions  176   a  and  176   b  in the platform  110 . In addition, outer generally longitudinally extending ribs  152  extend between the front end  120   a  of the platform  110  and the back end  120   b . The outer ribs  152  generally follow the outside edge of the platform  110 , tapering inward near the first and second neck sections  116   a  and  116   b  to extend along a central region of the first and second neck sections  116   a  and  116   b.    
     The front platform section  112  and the rear platform section  114  provide comparatively stiff sections of the platform  110 , on which a rider can place their feet during operation of the caster board  100 . The neck region  106  of the caster board  100  is less resistant to twisting than the front platform section  112  and the rear platform section  114 , due to the comparatively narrow cross-sectional shape of the neck region  106  and the inclusion of the aperture  160  extending therethrough. However, the neck region  106  of the board may still be provided with sufficient vertical support to resist significant downward bowing when a rider places their foot on the neck region. In some embodiments, the taller vertical sidewall along the outer edge  126   a  of first neck section  116   a  and outer edge  126   b  of second neck section  116   b  in the neck section  106  may provide resistance to flexure away from the longitudinal axis  108  of the caster board  100 . 
     Because the front platform section  112  and the rear platform section  114  are more resistant to twisting than the neck section  106 , the shape of the front platform section  112  and the rear platform section  114  will remain generally constant during operation, even during twist-induced locomotion, providing a more stable riding experience for the rider. The neck section  106  can be configured to resiliently twist during operation of the board  100 , as discussed in more detail below. In some embodiments, the neck section  106  twists about a longitudinal axis of the board  100 . The neck section  106  can be configured to provide sufficient twisting resistance and resiliency to enable normal riding operation of the board  100 . Several embodiments do not require and/or include a separate torsion strut located outside of the neck section  106 . For example, various embodiments do not have a torsion bar that is positioned under the neck section  106  and/or not in the same plane as the neck section  106 , which would limit the ground clearance, increase complexity, add weight, and/or reduce the size of insert that could received in the aperture  160 . In several embodiments, from a top view (see  FIG.  3   ), no portions of the board  100  are visible through the aperture  160  and/or a user on the board  100  has an unimpeded view to the ground through the aperture  160 . 
     In operation, because the caster assemblies  130   a  and  130   b  are located beneath the front platform section  112  and the rear platform section  114 , respectively, the caster assemblies  130   a  and  130   b  will be reoriented in response to tilting of the overlying platform section. In particular, this tilting may be due to the application of a force which is laterally offset from the longitudinal axis  108  of the caster board  100 . 
     During operation of the caster board  100 , or of any skateboard, a rider may align their weight with the longitudinal axis  108  of the caster board  100  in order to inhibit or prevent tilting of the deck of the skateboard and continue moving in the current direction without changing course. If a rider wishes to steer the skateboard, a rider may shift their weight such that one or both of their feet are applying force in an offset manner, such as by rotating their body, rocking on their feet, and/or shifting their weight and/or foot positions, in order to control the movement of the skateboard. A caster board such as caster board  100  may be operated in a similar fashion. 
       FIG.  11 A  illustrates an embodiment of a caster board  200  with caster assemblies  230   a  and  230   b  shown in outline to illustrate the positions of the front and rear wheels  232  and the forks  240 . In  FIG.  11 A , the rider is positioned on the board such that their weight is substantially aligned at both the front platform section  212  and the rear platform section  214  with the longitudinal axis  208  of the board. The net force  292  acting on the front platform section  212  is aligned with the longitudinal axis  208 , as is the net force  294  acting on the rear platform section  214 . The deck  210  does not tilt under this loading, and the wheels  230  of the caster assemblies  230   a  and  230   b  remain aligned with the longitudinal axis  208  of the board  200 , and the board  208  continues moving forward in the same direction. 
     In  FIG.  11 B , the caster board  200  is steered in a similar manner as a traditional skateboard. The rider has shifted their weight to the left side of the skateboard at both the front platform section  212  and the rear platform section  214 . The net forces  292  and  294  acting on the front and rear platform sections  212  and  214 , respectively, are laterally offset in the same direction from the longitudinal axis  208 , and the board  208  will tilt to the left without twisting. Because the caster assemblies  230   a  and  230   b  trail their respective mounting points, the caster assemblies  230   a  and  230   b  swing in a counterclockwise direction, reorienting the wheels  232  as shown. The board  200  will then turn to the left in response to the rider&#39;s shift in position. 
     In some embodiments, the caster board  200  may be configured such that a small force differential will not result in significant twisting of the board.  FIG.  11 C  illustrates a state in which there is a small force differential between the front and rear portions of the caster board, insufficient to result in significant twisting of the board. It can be seen that the net force  292  acting on the front platform section  212  is laterally offset slightly to the right of the longitudinal axis  208 , although the net torque applied by this offset is small, due to the small offset. Similarly, the net force  294  acting on the rear platform section  214  is laterally offset slightly to the left of the longitudinal axis  208 , applying a small net torque in the opposite direction. The opposing forces of similar magnitude do not result in tilting of the board either to the left or the right, just as a traditional skateboard would not be tilted under the same loading. 
     Because the platform  210  of the caster board  200  has some resistance to twisting, the front platform section  212  does not twist substantially with respect to the rear platform section  214 , so that neither the front platform section  212  nor the rear platform section  214  assume a tilted position with respect to the neutral position of the platform  210 . Within a certain range of applied force, the caster board  200  operates in a manner similar to a traditional skateboard, allowing a rider to use the caster board  200  in a fashion similar to a traditional skateboard. 
     At higher applied force differentials, however, the operation of the caster board diverges from that of a traditional skateboard.  FIG.  11 D  illustrates a state in which there is a large force differential between the front and rear portions of the caster board, sufficient to result in significant twisting of the board. It can be seen that the net force  292  acting on the front platform section  212  is laterally offset significantly to the right of the longitudinal axis  208 . This significant offset results in substantial net torque being applied at the front platform section  212 . Similarly, the net force  294  in acting on the rear platform section  214  is laterally offset significantly to the right of the longitudinal axis  208 , resulting in a substantial net torque in the opposite direction being applied at the rear platform section  214 . 
     For a stiff traditional skateboard with significant resistance to twisting, the large force differential will not result in tilting of the deck of the skateboard so long as the net torques are similar in magnitude and opposite in direction. Such a traditional skateboard will, under this loading, continue moving in the same direction. 
     In contrast, the caster board  200  will behave differently than a traditional skateboard under this loading. In the caster board  200 , the front platform section  212  is connected to the rear platform section  216  by a narrower divided neck portion  206  with substantially less torsional stiffness than a traditional skateboard or the front and rear platform sections  212  and  214 . The force differential will result in twisting of the platform  210 , where the twisting is primarily localized in the narrower divided neck portion  206 , so that the front platform portion  212  tilts to the right, and the rear platform portion  214  tilts to the left. The rightward tilt of the front platform portion  212  will result in the caster assembly  230   a  rotating in a clockwise direction, and the leftward tilt of the rear platform portion  214  will result in the caster assembly  230   b  rotating in a counterclockwise direction. 
     If the rider then shifts their weight in the opposite direction, the board will twist back through a neutral shape and twist in the opposite direction.  FIG.  11 D  illustrates a loading condition of a caster board which is the opposite of the loading condition depicted in  FIG.  11 E . The force differential will again result in twisting of the platform  210 , but under this loading, the front platform portion  212  tilts to the left, and the rear platform portion  214  tilts to the right. The leftward tilt of the front platform portion  212  will result in the caster assembly  230   a  rotating in a counterclockwise direction, and the rightward tilt of the rear platform portion  214  will result in the caster assembly  230   b  rotating in a clockwise direction. 
     In addition to swinging outward from the longitudinal axis  208  as shown in  FIGS.  11 D and  11 E , the wheels  232  of the caster assemblies  230   a  and  230   b  will not remain vertical but will instead be canted inward towards the longitudinal axis  208  of the caster board  200 . As a rider repeatedly shifts their weight to vary the loading between the loading illustrated in  FIG.  11 D  and the loading illustrated in  FIG.  11 E , the twisting motion of the caster board  200  will generate or maintain forward movement of the caster board  200 , allowing a rider to propel themselves without the need to push their foot against the ground to propel the caster board  200  forward. The relative rotation of different sections of the platform  210  about the longitudinal twist axis  208  of the caster board  200  changes the angle at which the weight of the rider is applied to each of the caster assemblies  230   a  and  230   b , causing them to rotate about their pivot axes. This rotational movement of the caster assemblies  230   a  and  230   b  can be used to add energy to the rolling motion of each wheel  232  of the caster assemblies  230   a  and  230   b  about its rolling axis and can be used to steer the caster board  200 . 
     For example, a rider may maintain the position of their right foot on rear platform section  214  generally perpendicular to the longitudinal axis  208  of the caster board  200  and parallel to the ground, and maintain the position of their left foot on front platform section  212  generally perpendicular to the longitudinal axis  208  of the caster board  200  and parallel to the ground. If the rider, while in this position, lowers the ball of their front foot and/or lifts the heal of their front foot, the front platform section  212  will twist clockwise relative to the rear platform section  214  when viewed from the rear of the caster board  200 . This twist of the front platform section  212  causes the weight of the rider to be applied to the wheel  232  of the front caster assembly  230   a  at an angle to the ground, rather than orthogonal to the ground, causing the wheel  232  to begin to roll, to maintain a previous rolling motion, and/or to increase the speed of motion of the caster board  200  by adding energy to the rolling motion of the wheels. 
     The rider can cause such a twist of platform  210  of board  200  in several ways, which may be used either alone or in combination. For example, the rider can cause such a twisting motion of the platform  210  by twisting or rotating their body, applying pressure with the toe of one foot while applying pressure with the heel of the other foot, by changing foot positions and/or by otherwise shifting their weight. To provide substantial locomotion, the rider can first cause a twist along longitudinal axis  208  in a first direction and then reverse their operation and cause the platform to rotate back through a neutral position and then into a twist position in the opposite direction. While moving forward, the rider can use the same types to motion, but at differing degrees, to control the twisting to steer the motion of board  200 . 
     In the illustrated embodiments, the neck region  206  of the caster board has an asymmetrical shape, due to the angle of the neck portions relative to the longitudinal axis  208  of the caster board. This asymmetrical shape causes a corresponding asymmetrical variation in torsional stiffness along the length of the neck portion  206 , with the narrower portion of the neck portion  206  adjacent the rear platform  214  having the lowest torsional stiffness. 
       FIG.  12    illustrates a plot of relative twist angle along the length of a platform in response to an applied torque. It can be seen in the plot  390  of relative twist angle as a function of longitudinal position along the platform, that the bulk of the twist is localized within the neck region  306 , with little change in twist angle over the front region  302  containing a wider front platform section or over the rear region  304  containing a wider rear platform section. 
     For a platform with a longitudinally symmetric neck design along the length of the neck, the relationship between twist angle and position may be linear within the neck portion, or may be at least partially non-linear with an inflection point at the center of the neck region, depending on the specific design of the neck. An example of such a relationship is shown as line  394 . However, it can be seen that the change in twist angle as a function of position in section  392  of plot  390  is more concentrated within a narrower portion of the asymmetric neck region  306 , where the torsional stiffness of the neck region  306  is at a minimum. 
     The asymmetrical design of certain embodiments described herein, in which the thinnest portion of the neck region is located near the rear platform section, may provide certain advantages for a rider. A rider may be more likely to utilize their dominant foot as their rear foot. As such, the locomotion of the caster board may be primarily driven by the motion of the rear, dominant foot. By reducing the torsional stiffness of the neck region near the rear platform, it may be easier for a rider to propel themselves forward using the repetitive twisting motion described above. 
     In some embodiments, the caster board may be configured to receive one or more inserts into an aperture extending into or through the neck region of the caster board. The caster board can include one or more securing features to hold an insert in place within the aperture, such as stops, clasps, clamps, detents, levers, friction fits, magnets, or otherwise. The caster board can be configured such that the insert can be readily removable from the aperture, such as by deactivating (e.g., loosening) a securing feature and/or by pulling the insert out of the board in a direction generally perpendicular to the deck (e.g., upward). The insert can have a peripheral shape that corresponds to the peripheral shape of the aperture. 
       FIG.  13    is an exploded view of a caster board and an insert dimensioned to fit within the aperture in the caster board. The caster board  400  includes an aperture  460  located between first and second neck sections  416   a  and  416   b . The aperture includes a chamfered upper portion  468  adjacent the upper surface of the platform  410  and/or substantially vertical sidewalls  462 . Certain embodiments may include apertures having other designs, as discussed herein. 
     In the illustrated embodiment, an insert  480  is dimensioned to fit within the aperture  460 , with an outwardly extending portion  482  near the upper surface of the insert  480 . The outwardly extending portion  482  may cooperate with the chamfered upper portion  468  of the aperture  460  to inhibit or prevent the insert  480  from falling through the aperture  460 , and/or to define an upper surface which is at least somewhat coplanar or otherwise contiguous with the surrounding upper surface of the platform  410 . In some embodiments, when installed in the aperture, an upper surface of the insert is generally flush with the upper surface of the platform. In some variants, the upper surface of the insert is recessed below the upper surface of the platform or projects above the upper surface of the platform. In some embodiments, the upper surface of the insert is generally flat and/or is contoured to match and/or to be an extension of the contours of the platform adjacent the aperture. This can make it appear that the insert is part of the platform and/or can provide additional space for the user to position a body part (e.g., can put some or all of a foot on the upper surface of the insert). 
     A wide variety of other insert shapes may also be used. In some embodiments, the aperture may include one or more rails, notches, grooves or other retention structure, which may cooperate with a corresponding structure on an insert to provide a more secure fit between the insert and the caster board. In some embodiments, an insert may occupy only a portion of the aperture, leaving another portion of the aperture free from an insert. Because the aperture may have a longitudinally and/or vertically asymmetrical shape, such as is shown, the shape of the insert may compel a particular orientation of the insert relative to the aperture. For example, the insert may be insertable into the aperture in only a single orientation. In some embodiments, for example, an insert may have a length less than that of the aperture, but a width and shape that requires that the insert be inserted at the widest point of the aperture, adjacent the front platform section. 
     In various embodiments, the inserts may include a wide variety of mechanisms or components and may be used for a wide variety of purposes. For example, in some embodiments, the insert is configured to alter a mechanical or structural property of the caster board when inserted into the aperture in in the caster board. This can beneficially allow riders to customize the properties of the caster board based on a variety of factors, including their body size, skill level, riding environment, current activity, or any other suitable factor. 
     In some embodiments, the insert can comprise an elastomer or other material that can be added to the gap, and which can adjust the effective spring rate of the neck to alter the torsional stiffness of the neck region. Adjusting the effective spring rate of the neck and/or the torsional stiffness of the neck can change the magnitude of torque required to twist the neck and pivot the front platform section of the caster board relative to the rear platform section of the caster board. The change in torsional stiffness can alter the mechanical properties of the caster board, such as steering or stability. 
     In some embodiments, a weight or series of weights can be affixed to the neck or added to the gap using some attachment mechanism. The weight or weights can be fixed to a specific location or movable to different locations on the neck. The weight or weights can be of different masses. Adding mass to the neck or shifting the location of mass supported by the neck, can alter the mechanical properties of the caster board, such as steering or stability. 
     In some embodiments, the caster board may not undergo significant twisting under a certain torque threshold, so that the caster board can be operated in a manner similar to that of a traditional skateboard. Increasing the stiffness of the neck portion can increase the torque threshold required to twist the front platform section relative to the rear platform section, which may alter the riding experience while using such a caster board. For example, a rigid or semi-rigid insert may increase the torque threshold required to cause significant twisting of the front platform section relative to the rear platform section, making it easier for a rider to operate the caster board as a traditional skateboard, without inducing undesired twisting. This may provide a rider with the flexibility to operate the caster board as a traditional skateboard when desired, and remove the insert to facilitate operation as a caster board and induce locomotion of the board across a riding surface via repetitive twisting of the front and rear platforms relative to one another. 
     In some embodiments, the insert may perform a function other than structural modification of the caster board. For example, in some embodiments, the insert can comprise an electronic device, such as a light, speaker, camera, sensor system, or any other suitable electronic device. 
     Any of the electronic devices insertable into the aperture could include controls on the insert itself, or could be configured to communicate with an external device, such as a smartphone, tablet, or computer, which could be used to modify the characteristics of the electronic devices, control the operation of the electronic devices, or power the electronic devices on or off. An insert including an electronic device may include a wireless communication module configured to allow communication with an external device. 
     An insert including an electronic device may include a power source. In some embodiments, a device may include an integrated power source, such as a rechargeable battery. In some embodiments, a device may be configured to receive a removable battery or other suitable power source. 
     A light or series of lights can create a variety of visual effects, such as a glow, headlight, or safety warning. In some embodiments, one or more lights may be used as a safety feature to increase visibility of a rider at night. In some embodiments, a lower surface of the insert may include a downlight configured to illuminate the ground underlying the caster board. In some embodiments, light may be emitted in any desired direction. Such a light may be monochrome or multicolor, and may in some embodiments a user may control the operation of the light vary the color, brightness, illumination pattern or rate, or other characteristic of the emitted light. 
     A speaker or speakers can create a variety of audible effects, such as music, sound effects, or alarms. A speaker may include internal storage configured to store music, such as a removable or integrated memory, memory card, or other storage medium, so that no connection with an external device is required to play music. In some embodiments, a wireless connection may be made with an external device such as a smartphone to stream or transmit an audio signal or audio file to a speaker insert for playback. 
     A camera or series of cameras can be used to capture image data such as photographs or videos, including while riding the caster board. The camera may be configured to use an interchangeable lens and/or filter to vary a characteristic of the captured image or video data. The captured image or video data may be saved to a local memory within the insert, or may be transmitted or streamed to an external device. 
     In some embodiments, the insert may include one or more sensors or sensor systems. Examples of sensors which could be included in an insert include: an accelerometer, GPS tracker, or other measurement or navigation device. Sensors and sensor systems can be used to measure, record, or display a variety of measurements or physical characteristics, such as time, velocity, or location. Sensor systems can also be used to locate the caster board, including when the caster board is lost, stolen, or misplaced. Embodiments of sensors or sensor systems can be configured to communicate with an external device, to provide sensor output and/or to control the operation of the sensors. 
     In some embodiments, a locking mechanism may be used to securely retain an insert in place, and to inhibit or prevent its removal, particularly when the insert may include GPS or other location sensors which can provide an indication of the location of the caster board as a security feature. 
     In some embodiments, the insert may not itself comprise an electronic device, but may instead comprise a mounting system for a separate device, such as an external phone, camera, speaker, or other device. The separate mounted device can be used to record video, take photographs, play audio, or perform other functions while riding the caster board. 
     A separate mounted device may be retained within the aperture, or may utilize the aperture to securely retain the separate device at a desired position relative to the caster board. For example, a camera mount may allow an offset mounting of a camera or other recording device at the edge of the caster board or at a distance from the caster board, which may provide a more suitable angle for recording video, images, and/or audio. The mounting system can be used to store or secure a phone, camera, speaker, or other device while riding the caster board. 
     In some variants, the caster board can stow a mobile electronic device, such as a cellphone. For example, in some embodiments, the aperture is configured to removably receive and securely retain the mobile electronic device. In certain variants, the insert comprises a chamber that is configured to removably receive and securely retain the mobile electronic device. A friction fit and/or one or more locking members (e.g., straps, elastic bands, clasps, detents, etc.) can hold the mobile electronic device in position. 
     In some embodiments, the neck can include a performance accessory such as a groove, tube, or other surface for grinding. Grinding refers to a maneuver where a caster board rider slides the caster board along another surface, such as the edge of a ramp, box, ledge, or pole. Grinding can wear or damage a caster board. Adding a groove, tube, or other grinding surface to the neck can make it easier for caster board riders to perform a grinding maneuver and can increase the durability of a caster board while grinding. 
     Because certain embodiments described herein may utilize a neck region, such as the illustrated split neck regions, as the primary torsion element, there may be no need to include a separate torsion bar underlying and connecting the front platform section to the rear platform section. Because of the lack of a torsion bar, a centrally located aperture which is aligned with a longitudinal axis of the caster board may expose a space underlying the caster board platform which would otherwise be occupied by a torsion bar. 
     Certain inserts may occupy or otherwise make use of this open space. For example, in an embodiment in which the insert includes a downlight, the lack of an underlying torsion bar may allow more effective illumination of the area underlying the aperture. In an embodiment in which the insert includes a performance accessory, the additional space provided by the lack of an underlying torsion bar may give greater flexibility as to the type and size of performance accessories which may be used. 
     In some embodiments, a storage compartment can be added to the aperture or secured relative to the caster board using the aperture. The storage space can be used to store or secure a variety of items within the caster board, such as keys, a wallet, or an identification card. Items can be stored or secured in the storage space while riding or transporting the caster board. In some embodiments, a storage compartment may be secured in place using the aperture but may, for example, occupy a portion of the area underlying the aperture to provide additional storage space which may be larger or of a different shape than the aperture itself. 
     In some embodiments, a block or locking mechanism can be added to the gap. The block or locking mechanism can inhibit or prevent the caster board platforms from pivoting relative to each other, which would inhibit or prevent a user from operating the caster board as normal. In some embodiments, the block or locking mechanism can be removed using a key, passcode, or other unlocking device. The block or locking mechanism may be removed via direct interaction with the block or locking mechanism, or by indirect interaction with the block or locking mechanism via an external device such as a phone or tabled. The block or locking mechanism can function as an anti-theft device that could inhibit or prevent an individual from stealing and riding another individual&#39;s caster board without permission. The block or locking mechanism can be configured to stabilize the caster board when not in use, such as when shipping or transporting the caster board. 
     In some embodiments, a magnet or magnetic surface can be affixed to the neck, or added to the gap, using an attachment mechanism. A magnet or magnetic surface can be used to secure the caster board when attaching the caster board to a magnetic wall mount. A magnet or magnetic surface can also be used to affix magnets or other items to the caster board for either aesthetic or functional purposes. 
     In some embodiments, a spark generating device or structure can be added to the neck. A spark generating device can include spark pads or a spark plate made from flint or another material that generates sparks when in contact with a surface such as cement, asphalt, or metal. The spark generating device can be added to the neck using an adhesive or other attachment mechanism. Sparks can be desirable because they may create an appealing visual or audible effect. 
     In some embodiments, an insert may itself include an aperture extending at least partially therethrough. For example, in some embodiments, an insert having an outer dimension specific to the caster board may be used as an adapter to define a smaller aperture more suitable for retaining at least a portion of another device or structure. In such an embodiment, an adapter insert may be used to allow securement of another device or mechanism relative to the caster board, such as an existing consumer electronics device, which was not explicitly designed for use with a given caster board. 
       FIG.  14    is a flow diagram illustrating an exemplary process for modifying a structural property of a caster board using an insert. The process  500  begins at a stage  505  where a caster board is provided, the caster board including an aperture extending into the platform. In some embodiments, the aperture may extend completely through the platform. In some embodiments, the aperture may extend through only a portion of the platform. In some embodiments, the aperture may include a chamfered section, or a section which is otherwise tapered or dimensioned to receive an insert. In some embodiments, the aperture may be longitudinally asymmetrical, with a width that varies over the longitudinal length of the aperture. 
     The process  500  then moves to a stage  510  where a structural element is inserted into the aperture to adjust a structural property of the caster board. In some embodiments, the structural element may include an insert configured to adjust a torsional stiffness of the caster board. In some embodiments, the structural element may be configured to adjust the mass of a portion of the caster board, or a distribution of mass across a caster board. In other processes, any other type of insert, such as an insert including an electronic device, may be inserted into the aperture. 
     The present disclosure includes ornamental aspects of the caster boards and such ornamental aspects may be claimed. Some such claims encompass only part of the disclosed caster boards. For example, the caster wheels, fasteners, parting and/or sculpting lines, ribs (e.g., the ribs  152 ,  154 ), and/or recesses (e.g., the depressions  176   a ,  176   b ) and features therein may be disclaimed. In some embodiments, the ornamental features shown in  FIG.  3    (less, e.g., depressions  176   a ,  176   b  and features therein) are claimed. 
     While certain embodiments have been described, these embodiments have been presented by way of example only and are not intended to limit the scope of the disclosure. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions and changes in the systems and methods described herein may be made without departing from the spirit of the disclosure. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope of the disclosure. 
     Features, materials, characteristics, or groups described in conjunction with a particular aspect, embodiment, or example are to be understood to be applicable to any other aspect, embodiment or example described in this section or elsewhere in this specification unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The protection is not restricted to the details of any foregoing embodiments. The protection extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed. 
     Furthermore, certain features that are described in this disclosure in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations, one or more features from a claimed combination can, in some cases, be excised from the combination, and the combination may be claimed as a subcombination or variation of a subcombination. 
     For purposes of this disclosure, certain aspects, advantages, and novel features are described herein. Not necessarily all such advantages may be achieved in accordance with any particular embodiment. Thus, for example, those skilled in the art will recognize that the disclosure may be embodied or carried out in a manner that achieves one advantage or a group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein. 
     Certain terminology may be used in the following description for the purpose of reference only, and thus is not intended to be limiting. For example, terms such as “upper”, “lower”, “upward”, “downward”, “above”, “below”, “top”, “bottom”, “left”, and similar terms refer to directions in the drawings to which reference is made. Such terminology may include the words specifically mentioned above, derivatives thereof, and words of similar import. Similarly, the terms “first”, “second”, and other such numerical terms referring to structures neither imply a sequence or order unless clearly indicated by the context. 
     Conditional language, such as “can,” “could,” “might,” or “may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements, and/or steps. Thus, such conditional language is not generally intended to imply that features, elements, and/or steps are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without user input or prompting, whether these features, elements, and/or steps are included or are to be performed in any particular embodiment. 
     Conjunctive language such as the phrase “at least one of X, Y, and Z,” unless specifically stated otherwise, is otherwise understood with the context as used in general to convey that an item, term, etc. may be either X, Y, or Z. Thus, such conjunctive language is not generally intended to imply that certain embodiments require the presence of at least one of X, at least one of Y, and at least one of Z. 
     Terms relating to circular shapes as used herein, such as diameter or radius, should be understood not to require perfect circular structures, but rather should be applied to any suitable structure with a cross-sectional region that can be measured from side-to-side. Terms relating to shapes generally, such as “spherical” or “circular” or “cylindrical” or “semi-circular” or “semi-cylindrical” or any related or similar terms, are not required to conform strictly to the mathematical definitions of spheres, circles, cylinders or other structures, but can encompass structures that are reasonably close approximations. 
     The terms “approximately,” “about,” and “substantially” as used herein represent an amount close to the stated amount that still performs a desired function or achieves a desired result. For example, in some embodiments, as the context may permit, the terms “approximately”, “about”, and “substantially” may refer to an amount that is within less than or equal to 10% of the stated amount. The term “generally” as used herein represents a value, amount, or characteristic that predominantly includes or tends toward a particular value, amount, or characteristic. As an example, in certain embodiments, as the context may permit, the term “generally parallel” can refer to something that departs from exactly parallel by less than or equal to 20 degrees. As another example, in certain embodiments, as the context may permit, the term “generally perpendicular” can refer to something that departs from exactly perpendicular by less than or equal to 20 degrees. 
     The terms “comprising,” “including,” “having,” and the like are synonymous and are used inclusively, in an open-ended fashion, and do not exclude additional elements, features, acts, operations, and so forth. Likewise, the terms “some,” “certain,” and the like are synonymous and are used in an open-ended fashion. Also, the term “or” is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term “or” means one, some, or all of the elements in the list. 
     Some embodiments have been described in connection with the accompanying drawings. The figures are drawn to scale, but such scale is not limiting, since dimensions and proportions other than what are shown are contemplated and are within the scope of the disclosed invention. Distances, angles, etc. are merely illustrative and do not necessarily bear an exact relationship to actual dimensions and layout of the devices illustrated. Components can be added, removed, and/or rearranged. Further, the disclosure herein of any particular feature, aspect, method, property, characteristic, quality, attribute, element, or the like in connection with various embodiments can be used in all other embodiments set forth herein. Additionally, any methods described herein may be practiced using any device suitable for performing the recited steps. 
     Overall, the language of the claims is to be interpreted broadly based on the language employed in the claims. The language of the claims is not to be limited to the non-exclusive embodiments and examples that are illustrated and described in this disclosure, or that are discussed during the prosecution of the application. 
     Although the invention has been disclosed in the context of certain embodiments and examples, it will be understood by those skilled in the art that this disclosure extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses of the embodiments and certain modifications and equivalents thereof. The scope of the present disclosure is not intended to be limited by the specific disclosures of preferred embodiments in this section or elsewhere in this specification, and may be defined by claims as presented in this section or elsewhere in this specification or as presented in the future.