Abstract: An engine includes a crankshaft rotatable about a crankshaft axis. A compression piston is slidably received within a compression cylinder and operatively connected to the crankshaft such that the compression piston is operable to reciprocate through an intake stroke and a compression stroke during a single rotation of the crankshaft. An expansion (power) piston is slidably received within an expansion cylinder and operatively connected to the crankshaft such that the expansion piston is operable to reciprocate through an expansion stroke and an exhaust stroke during a single rotation of the crankshaft. A variable volume crossover passage interconnects the compression and expansion cylinders, and includes a variable volume housing to controllably regulate the air flow from the compression cylinder to the expansion cylinder.

Abstract: An engine includes a crankshaft rotatable about a crankshaft axis. A compression piston is slidably received within a compression cylinder and operatively connected to the crankshaft such that the compression piston is operable to reciprocate through an intake stroke and a compression stroke during a single rotation of the crankshaft. An expansion (power) piston is slidably received within an expansion cylinder and operatively connected to the crankshaft such that the expansion piston is operable to reciprocate through an expansion stroke and an exhaust stroke during a single rotation of the crankshaft. A variable volume crossover passage interconnects the compression and expansion cylinders, and includes a variable volume housing to controllably regulate the air flow from the compression cylinder to the expansion cylinder.

Abstract: A shoe, boot and skate holder includes a handle, a stem extending from the handle, and a locking mechanism operatively connected to the stem. An eyelet rod is releasably lockable in the locking mechanism. The eyelet rod is insertable through eyelets of a shoe, boot or skate, and is lockable in the locking mechanism to retain the shoe, boot or skate in the holder.

Abstract: A shoe, boot and skate holder includes a handle, a stem extending from the handle, and a locking mechanism operatively connected to the stem. An eyelet rod is releasably lockable in the locking mechanism. The eyelet rod is insertable through eyelets of a shoe, boot or skate, and is lockable in the locking mechanism to retain the shoe, boot or skate in the holder.

Abstract: A skate device, e.g., a skate or skate board, includes a foot support device, e.g., a boot or a board, and a truck assembly for supporting the foot support device. The truck assembly has a first wheel housing mounted in pivotal relation to the foot support device. A first wheel has a first axle mounted to the first wheel housing for rotation about a first wheel axis. A first spring housing is mounted in fixed relation to the foot support device. A centering spring is mounted within the first spring housing and engages the first wheel housing to pivotally urge the first wheel toward a predetermined first center position.