| 摘要 |
A pressure fluid power driving device for driving studs, nails or the like having a gas chamber including an accumulator piston movable against the force of the gas in the chamber by the action of a noncompressible fluid against the accumulator piston. The invention further relates to the use of noncompressible fluid acting at a first, relatively low pressure to force a brake spool to carry a ram upwardly into sealing engagement with a seat element. The ram is propelled downwardly with great velocity when noncompressible fluid at a second, relatively high pressure, enters the cylinder to urge the accumulator piston against the bias of the compressed gas until a predetermined pressure level is achieved within the cylinder wherein an automatic pressure relief valve system breaks the seal between the top of the drive piston and the seating element allowing the full force of the compressed gas to act on the upper surface of the drive piston through the noncompressible fluid. |
