Abstract: The latest in a series of wheelchair lift improvements is provided, the basic lift structure on which the improvements are made being the type utilizing a step configuration, the individual panels of which, being hinged together, are simply extended into a geometrical plane rather than a step structure. The resulting platform is then elevationally adjusted by the driver to commute the platform, and a wheelchair victim on the platform, between the curb and bus floor level. The improvements include the hydraulic drive for deploying the mechanism between step and platform mode, the safety barrier structure which defines an extension of the platform to the curb level when it is dropped from its safety barrier mode, a safety locking mechanism and a stablizing chain.

Abstract: The latest in a series of wheelchair lift improvements is provided, the basic lift structure on which the improvements are made being the type utilizing a step configuration, the individual panels of which, being hinged together, are simply extended into a geometrical plane rather than a step structure. The resulting platform is then elevationally adjusted by the driver to commute the platform, and a wheelchair victim on the platform, between the curb and bus floor level. The improvements include the hydraulic means of deploying the mechanism between step and platform mode, the safety barrier structure which defines an extension of the platform to the curb level when it is dropped from its safety barrier mode, a safety locking mechanism and a stabilizing chain.

Abstract: A single stage, twin piston cryogenic refrigerator for cooling supercondung devices. The refrigerator uses helium as the heat transfer medium and is constructed with two nested, concentric pistons, an inner piston and an outer piston, mounted in a cylinder and driven 90.degree. out of phase by a common crankshaft. The inner piston extends through and below the outer piston and is received in a stationary insert mounted in the cylinder. The outer piston has a first piston face which forms a compression space with the stationary insert while the inner piston has a second piston face which forms an expansion space with the cylinder and the insert. The inner piston is formed with upper and lower piston halves joined by a flexible joint positioned in the compression space. Cylindrical regenerator gaps are present at the interface of the inner piston with the stationary insert and at the interface of the stationary insert with the cylinder.

Abstract: The latest in a series of wheelchair lift improvements is provided, the basic lift structure on which the improvements are made being the type utilizing a step configuration, the individual panels of which, being hinged together, are simply extended into a geometrical plane rather than a step structure. The resulting platform is then elevationally adjusted by the driver to commute the platform, and a wheelchair victim on the platform, between the curb and bus floor level. The improvements include the hydraulic drive for deploying the mechanism between step and platform mode, the safety barrier structure which defines an extension of the platform to the curb level when it is dropped from its safety barrier mode, a safety locking mechanism and a stabilizing chain.