Pile driving device
OwnerBirger Ludvigsoninventor
Life of this patent
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Abstract
A gas cushion impact cap, used in connection with pile driving, is connected to an external pressure chamber holding an additional volume of gas, whereby there will be no appreciable change in the gas pressure during the impact. The gas pressure is primarily determined by varying the volume of a liquid contained in the pressure chamber, in response to the resistance met by the pile while penetrating the ground. The impact cap may be pre-loaded during an upwards movement, the pre-load being released upon the impact, to throw the hammer upwards again.
Claims13
A device for displacing an elongate member, for instance a pile by means of a drop hammer, comprising
- an -- impact cap for transferring impacts from said drop hammer to said elongate member, said impact cap enclosing a cylinder,
- a -- piston operable in said cylinder to define a gas chamber therein and having a portion extending outside of the cylinder for acting against said elongate member,
- a -- pressure chamber, separate from the impact cap,
- conduit means to communicate said gas chamber and said pressure chamber to form a closed gas volume, pumping means for supplying a pressurized liquid to said pressure chamber and valve means for governing the supply to, and spilling of liquid from said pressure chamber,
- a -- sensing means adjacent to the end of said elongate member acted upon by the impact cap for converting conditions in said elongate member, dependent upon the resistance met by said member during movements caused by impacts thereon, into transmittable signals, and
- means -- adapted to receive such signals and to actuate said valve means in response thereto for determining the volume of liquid in said pressure chamber.
Dependencies are inferred from the claim text.