Manual two-stage air pump

Abstract

A manually operated pump includes a pulley sheave oppositely wound with cord and rotatably mounted on a support element, a two-stage pump, and a reciprocal action shaft. The shaft is mounted eccentrically through the assembled pump, including through a clearance hole and slot in a main piston of the pump. The pump is a cylinder with a double-ended piston slidably mounted within and forming a main chamber at each end of the cylinder. An offset high pressure piston extends into the main chamber from each cylinder end for operation with offset high pressure chambers defined in each end of the double-ended piston. Passageways with differential air pressure valves lead from the slot to the main chambers, from the main chambers to the high pressure chambers, and from the high pressure piston to outlets. The user's rectilinear pulling motion on the pulley cords is translated into alternating rotary motion at the pulley sheave, the rotary motion is translated into alternating linear motion at the eccentric common shaft, and the linear motion eccentrically placed with regard to the axis of rotation causes the shaft to move in a sinusoidal pattern around and against the sides of the main piston slot thereby causing the main piston to reciprocate. The second stage compression in the high pressure chambers/pistons operates as the pressure at the device to be inflated exceeds the pressure of the first stage compressed air.