Patent ID: 8327752
Filing Date: 2012-12-11
Classification: F15B,F16J

Abstract:
1. A fluidic actuator comprising: a cylinder having an input port; a piston disposed at least partially within the cylinder, the piston having a diameter and including a piston ring groove around a circumference of the piston, the piston ring groove having a low pressure face and a high pressure face; a piston ring located against the low pressure face of the piston ring groove such that a space exists between an inside diameter of the piston ring and the piston ring groove, the piston ring having an outside diameter that is larger than the diameter of the piston to provide a seal between the piston ring and the cylinder when the actuator is pressurized; and a spring disposed in the piston ring groove adjacent to the piston ring and located against the high pressure face of the piston ring groove such that a gap exists between an inner diameter of the spring and the piston ring groove, wherein the spring preloads the piston ring to provide a seal between the piston ring and the low pressure face of the piston ring groove, thereby preventing leakage between a high pressure side of the actuator and a low pressure side of the actuator; wherein actuation fluid fills the gap between the spring and the piston ring groove and fills the space between the piston ring and the piston ring groove when the actuator is pressurized to exert a radially outward force on the piston ring, thereby enhancing the seal between the piston ring and the cylinder, wherein the piston ring is split from the inner diameter to the outer diameter to facilitate insertion of the piston ring into the piston ring groove, and wherein a plurality of piston rings are inserted within the piston ring groove, and wherein at least one of the piston rings is assembled within the piston ring groove such that an angular location of the split in the piston ring is different from the angular location of the split in an adjacent piston ring.