Patent ID: 7717301

Claim:
A piston device, comprising: a sleeve, having a first open end, a first closed end, and one hole, wherein said one hole is disposed around the periphery of said first closed end thereof; a casing pipe, having a second open end, a second closed end, and one through hole arranged on a lateral side thereof proximate to said second closed end, wherein said casing pipe being sheathed and connected to the sleeve by a manner that said second open end of the casing pipe is faced toward the first closed end of the sleeve; a first piston, being arranged to ensheathe the casing pipe therethrough at proximate the second closed end of the casing pipe for selectively covering and exposing the though hole by a reciprocate movement; a resilient member, being installed inside the sleeve and positioned between the first closed end of the sleeve and the first piston while ensheathing the casing pipe therethrough; a second piston, being arranged to ensheathe the sleeve at proximate the first open end of the sleeve; and a hollow piping, having a third open end, a fourth open end, and a groove on said fourth open end, wherein said third open end is interconnected to the first closed end of the sleeve, said fourth end is disposed inside the sleeve, said groove is accommodating the second open end of the casing pipe, and said resilient member is pressing against said third open end and said first piston.