Abstract: A power source (14) rotates an eccentric (20) engaged within the center of a relatively large drive roller (22) to rotate the drive roller while simultaneously orbiting the center of the drive roller about a circular path so as to cyclically advance and retract from piston assemblies (24) located within pump assemblies (16a-16d). Rotation of the eccentric (20) causes each piston assembly (24) to cyclically advance against and retract from a flexible diaphragm (26) to cause fluid entering the pump assembly to be forced out under pressure. Each diaphragm (26) is "backed" by a spring-loaded support (27) that resiliently pushes against the side of the diaphragm opposite the piston assembly.

Abstract: A power source (14) rotates an eccentric (20) engaged within the center of a relatively large drive roller (22) to rotate the drive roller while simultaneously orbiting the center of the drive roller about a circular path so as to cyclically advance and retract from piston assemblies (24) located within pump assemblies (16a-16d). Rotation of the eccentric (20) causes each piston assembly (24) to cyclically advance against and retract from a flexible diaphragm (26) to cause fluid entering the pump assembly to be forced out under pressure. Each diaphragm (26) is "backed" by a spring-loaded support (27) that resiliently pushes against the side of the diaphragm opposite the piston assembly.