Core sampling device

Abstract

The obtaining of undisturbed core samples of subsurface soils for analysis and study is disclosed. Percussion-type downhole drilling equipment uses compressed air directed internally of a pipe casing to actuate a percussion-type piston adjacent the bottom of a hole being drilled. A tubular adapter is mounted in a chuck at the lower end of a casing and house the piston and the adapter for rotation and for longitudinal movement relatively thereto. The adapter has a striking face interfacing with the piston and has its opposite end provided with pipe threads for connection of an open-ended core sampler which is preferably of the split-spoon type. The adapter is provided with ports at a location spaced axially away from the core sampler for exhaust air released by the percussion means during a power stroke upwardly and thus away from the core sampler. The adapter acts much like the head of a nail driving the core sampler into the earth formation to be sampled producing an uncontaminated earth sample undisturbed by the exhaust air. Once the sample has been obtained, the apparatus with adapter is withdrawn from the hole. The process may be repeated or the core sampler replaced by a standard downhole drill bit if further drilling is required.

Dependencies are inferred from the claim text.