A modular skateboard assembly for facilitating a user to employ a pair of skateboards in the convention of a skateboard or roller skates includes a pair of skateboards which each includes a pair of rollers that roll along a support surface. Each of the skateboards is attachable together such that the pair of skateboards extends along a common axis thereby facilitating the pair of skateboards to be employed in the common convention of skateboards. Furthermore, each of the skateboards is detachable from each other thereby facilitating the pair of skateboards to be employed in the common convention of roller skates. Each of the skateboards includes a pair of foot restraints to restrain a respective one of a user's feet.

An adjustable roller skate includes a skate device and a boot body. The boot body includes a base frame having a bottom side coupled to the skate device, an insole platform having a rear heel portion and a front toe portion frontwardly extended therefrom, and a vamp cover attached to the front toe portion of the insole platform. The insole platform is slidably coupled at the base frame to define an adjustable accommodating cavity between a rear end of the base frame and a front end of the insole platform, wherein the insole platform is frontwardly slid to extend the adjustable accommodating cavity at its maximum size and is rearwardly slid to reduce the adjustable accommodating cavity at its minimum size.

A human transportation device in the form of a variable length skateboard. The variable length skateboard provides a short embodiment allowing the rider greater handling and stopping ability and a long embodiment providing the rider with increased speed ability. The long and short embodiments can quickly and easily be transitioned between at any time or place by the insertion or extraction of at least one removable center deck section. The deck sections are coupled using thumb screw type fasteners and coupler plates thereby removing a need for tools to make the conversion between embodiments. The variable length skateboard provides its owner with multiple embodiments without having to purchase multiple skateboards.

A modular skateboard assembly for enabling a user to employ a pair of skateboards in the convention of a skateboard or roller skates includes a pair of skateboards which each includes a pair of rollers that roll along a support surface. Each of the skateboards is attachable to the other skateboard such that the pair of skateboards extends along a common axis thereby facilitating the pair of skateboards to be employed in the common convention of skateboards. Furthermore, each of the skateboards is detachable from the other skateboard thereby enabling the pair of skateboards to be employed in the common convention of roller skates. Each of the skateboards includes a pair of foot restraints to restrain the user's feet.

A size-adjustable sport shoe includes a shoe head, a shoe insole, and an adjusting telescopic device including a gear, a shaft gear, first and second gear racks, and handle. The first and second gear racks are located at two lateral sides of an elongated adjustment groove at the shoe head, wherein the upper surface of the second gear rack is lower than the upper surface of the first gear rack. The gear shaft is coupled between the gear and the handle. When the handle is folded perpendicularly to an axis direction of the gear shaft, the gear meshes with the first gear rack to lock up the shoe head at the shoe insole. When the handle is folded to coincide with the axis direction of the gear shaft, the gear meshes with the second gear rack to allow the shoe head to be slid from the shoe insole.

A size-adjustable sport shoe includes a shoe head, a shoe insole, and an adjusting telescopic device including a gear, a shaft gear, first and second gear racks, and handle. The first and second gear racks are located at two lateral sides of an elongated adjustment groove at the shoe head, wherein the upper surface of the second gear rack is lower than the upper surface of the first gear rack. The gear shaft is coupled between the gear and the handle. When the handle is folded perpendicularly to an axis direction of the gear shaft, the gear meshes with the first gear rack to lock up the shoe head at the shoe insole. When the handle is folded to coincide with the axis direction of the gear shaft, the gear meshes with the second gear rack to allow the shoe head to be slid from the shoe insole.

A size-adjustable sport shoe includes a shoe head, a shoe insole, and an adjusting telescopic device including a gear, a shaft gear, first and second gear racks, and handle. The first and second gear racks are located at two lateral sides of an elongated adjustment groove at the shoe head, wherein the upper surface of the second gear rack is lower than the upper surface of the first gear rack. The gear shaft is coupled between the gear and the handle. When the handle is folded perpendicularly to an axis direction of the gear shaft, the gear meshes with the first gear rack to lock up the shoe head at the shoe insole. When the handle is folded to coincide with the axis direction of the gear shaft, the gear meshes with the second gear rack to allow the shoe head to be slid from the shoe insole.

A transformable skate is provided, including: a shoe body; a frame, connected to the shoe body; at least one first fork support, connected to the frame on which at least one first wheel is mounted; and an adjustable assembly, including a base and at least two second fork supports on which at least two second wheels are respectively mounted, the base being adjustably positioned to and blocked by the frame and the at least two second fork supports being each adjustably positioned to and blocked by the base so that the at least two second fork supports are constructed and arranged to position the at least two second wheels in an inline arrangement or in a parallel arrangement.

A transformable skate is provided, including: a shoe body; a frame, connected to the shoe body; at least one first fork support, connected to the frame on which at least one first wheel is mounted; and an adjustable assembly, including a base and at least two second fork supports on which at least two second wheels are respectively mounted, the base being adjustably positioned to and blocked by the frame and the at least two second fork supports being each adjustably positioned to and blocked by the base so that the at least two second fork supports are constructed and arranged to position the at least two second wheels in an inline arrangement or in a parallel arrangement.

A modular, multi-part roller skate is provided. The multi-part roller skate includes a roller skate body, a front wheel assembly, a rear wheel assembly, a support surface for supporting a footwear of a user, and at least one securing element for securing the footwear to the support surface. The multi-part roller skate is configurable as a modular roller skate with a removable pair of rear wheels, an interchangeable modular roller skate and ice skate, and an interchangeable modular roller skate and cross-country ski/snowshoe. In some embodiments, the multi-part roller skate can also be configured as a length-adjustable skate with a length adjustable skate body that includes separate front and rear foot support structures.