Teams may use any commercially available fastener on their Robot. Examples include (but are not limited to) screws, nuts, washers, rivets, hinges, pins, rod ends, threaded rods, hose clamps, bushings, spacers, or standoffs. To be considered a legal “fastener” in the context of this rule, the primary function of the part must be to join or fasten together two otherwise legal parts. For example, a pre-fabricated non-VEX wheel (which would be illegal under VUR5) would not be considered a “fastener,” even though it may also technically serve the purpose of bridging the connection between tread and a shaft.
Recently, Q&A #1208 broadened the definition of “fastener” to include COTS bearings, linear bearings, sliders, and ball joints. The reasoning seems to be that a “fastener” is something whose sole purpose is to constrain the motion of other parts on the robot, even if that motion is not restricted in all axes.
Therefore, the question raised is: Are COTS belts also considered fasteners? Currently, the only VEXU legal belts are VEX Pro timing belts, but there are many other COTS belts, such as V-belts, round belts, and flat belts, along with timing belts that have different tooth profiles and dimensions than the available GT2 and HTD timing belts.
Belts act as a fastener in the sense that they link the motion of two or more pulleys together. While the pulleys themselves would not be fasteners as shown by the wheel example, the belt’s sole purpose is to constrain the motion of the pulleys, and thus could be considered a fastener under the expanded definition.