Abstract: A telescopic skateboard may include a pair of direction casters mounted for steering rotation on a twistable one piece skateboard. A center section may be made sufficiently narrower than outboard foot support areas so that the board may be twisted by a rider to add energy for rolling motion to wheels in the casters. The center section may also be made sufficiently resistant to bowing and twist so that the skateboard may be ridden as a conventional, non-flexible skateboard. The center section may include telescoping male and female portions and an extension control.

Abstract: A flexible skateboard may include a pair of direction casters mounted for steering rotation a twistable one piece skateboard. A center section may be made sufficiently narrower than outboard foot support areas which may be twisted by a rider to add energy for rolling motion to wheels in the casters. The center section may also be made sufficiently resistant to twist so that the skateboard may be ridden as a conventional, non-flexible skateboard.

Abstract: A flexible skateboard may include a pair of direction casters mounted for steering rotation on a twistable one piece skateboard. A center section may be made sufficiently narrower than outboard foot support areas so that the board may be twisted by a rider to add energy for rolling motion to wheels in the casters. The center section may also be made sufficiently resistant to bowing and twist so that the skateboard may be ridden as a conventional, non-flexible skateboard. Wells may be provided to resist twisting and provide gripping surfaces on the board for the rider's feet.

Abstract: A flexible skateboard may include a pair of direction casters mounted for steering rotation a twistable one piece skateboard. A center section may be made sufficiently narrower than outboard foot support areas which may be twisted by a rider to add energy for rolling motion to wheels in the casters. The center section may also be made sufficiently resistant to twist so that the skateboard may be ridden as a conventional, non-flexible skateboard.

Abstract: A pogo stick comprising a handlebar, a grip portion, and a footrest that is collapsible into a small volume for easy transportation and compact storage. The handlebar is provided with at least one elongate telescoping member, the grip portion is provided with removable grips, and the footrest is provided with pivotally mounted plates. The collapsible pogo stick incorporates a pneumatic spring of variable stiffness for accommodating users of different body weights. The pneumatic spring includes a pressure cylinder and a shaft extending out of the cylinder for engagement with the ground. The pneumatic spring includes a self-charging mechanism such that the cylinder may be charged without the use of an external pump.

Abstract: A bicycle folding stem with positioning structure comprises a frame having a seat tube and a head tube. A seat post has a tube inserted into the seat tube of the frame to be lifted and lowered and to be secured at any position. A seat is mounted on an end of the seat post having a locking portion. A front fork has a tube inserted into the head tube of the frame and a fork body at the bottom end of the tube for pivoting a wheel. A stem is pivoted on the front fork at the top end thereof to be turned to the seat post for said seat post being lowered and said locking portion of said seat locked said stem.

Abstract: A pogo stick comprising a handlebar, a grip portion, and a footrest that is collapsible into a small volume for easy transportation and compact storage. The handlebar is provided with at least one elongate telescoping member, the grip portion is provided with removable grips, and the footrest is provided with pivotally mounted plates. The collapsible pogo stick incorporates a pneumatic spring of variable stiffness for accommodating users of different body weights. The pneumatic spring includes a pressure cylinder and a shaft extending out of the cylinder for engagement with the ground. The pneumatic spring includes a self-charging mechanism such that the cylinder may be charged without the use of an external pump.

Abstract: This invention is an improved boat hull design for stable operation as a planing-type hull in a wide range of water conditions. The hull is comprised of a substantially V-shaped central hull portion and a pair of adjacent side floats, one on each side of the central hull. The inner walls of the side floats are substantially vertical, and the floats are stepped upwardly at approximately midships, such that the rear portion of the side floats is substantially horizontal, or parallel to the plane of the water surface. At least one pair of flat surfaces are formed along the bottom portion of the hull positioned at the intersection of lowermost strakes and steps formed on each side of the hull, so as to provide substantially improved stability and attitude when running at high speed on rough water. A dihedral tunnel is formed by the concavely-curved surfaces of the central hull in combination with the inner walls of the side floats.

Abstract: A portable container includes an outer component defining a hopper-like compartment having a bottom opening and an inner component having a stopper centered in the hopper with respect to the bottom opening and shiftable into and out of stoppering relation to the bottom opening, the outer compartment suspending the inner component into axially slid hopper-stoppering position and there being a target within the lower end of the inner component; and a discharge hopper positioned below the bottom opening and including a lance for penetrating through the bottom opening into contact with the target to axially lift the stopper to unstoppering position in response to lowering of the outer component relative to the discharge hopper. The outer compartment contains a granular product or a mixture of products and the inner component may also contain a compatible product. The dry products of concrete or mortar may thus be stored.