Ingersoll-rand Company

Dresser-rand Company

Paul B Campbell

Robert R Kimberlin

James E Coffman

Paul W Crites

Ewald H Kurt

Roland P Holt

Sean M O'Malley

A compressor piston divides a first compartment into two compression chambers, while a hammer piston divides a second compartment into two drive chambers, each of the compression chambers being connected to a respective one of the drive chambers to form a closed fluid system wherein reciprocation of the compressor piston causes cyclic compression and expansion of the fluid in the compression chambers and thus in the drive chambers, to effect a cyclic impacting of the hammer piston with a bit adapter connected to the drill bit. A mud motor rotates a shaft to drive an oscillator which reciprocates the compressor piston. The oscillator can comprise roller elements in the compressor piston in engagement with canted grooves in the shaft. While drilling mud drives the motor and then passes downwardly to flush the drill bit and the borehole, the drilling mud is isolated from the closed fluid system. The bit adapter slides axially, so that when the drill bit is not in contact with a borehole bottom, the bit adapter and the hammer piston move downwardly to a position where the two drive chambers are in direct communication such that the reciprocation of the compressor piston does not actuate the hammer piston. Each of the pistons is an annular piston having a bleed passageway between its chambers, permitting the chambers to equalize when the pistons are stationary. The superatmospheric pressure is such that the hammer piston reciprocates at a frequency within .+-.20% of natural resonant frequency.

Percussion drill assembly

A compressor piston divides a first compartment into two compression chambers, while a hammer piston divides a second compartment into two drive chambers, each of the compression chambers being connected to a respective one of the drive chambers to form a closed fluid system wherein reciprocation of the compressor piston-causes cyclic compression and expansion of the fluid in the compression chambers and thus in the drive chambers, to effect a cyclic impacting of the hammer piston with a bit adapter connected to the drill bit. A mud motor rotates a shaft to drive an oscillator which reciprocates the compressor piston. The oscillator can comprise roller elements in the compressor piston in engagement with canted grooves in the shaft. While drilling mud drives the motor and then passes downwardly to flush the drill bit and the borehole, the drilling mud is isolated from the closed fluid system. The bit adapter slides axially, so that when the drill bit is not in contact with a borehole bottom, the bit adapter and the hammer piston move downwardly to a position where the two drive chambers are in direct communication such that the reciprocation of the compressor piston does not actuate the hammer piston. Each of the pistons is an annular piston having a bleed passageway between its chambers, permitting the chambers to equalize when the pistons are stationary. The superatmospheric pressure is such that the hammer piston reciprocates at a frequency within .+-.20% of natural resonant frequency.

An external surface of a splined nut

External surface of a splined nut

A fluid-activated, percussive impact tool has a piston therein that reciprocates longitudinally but not rotationally. The piston activates a wrap spring clutch to rotate the drill steel. A removable splined nut in combination with the tool's housing restrains rotation of the piston, while permitting longitudinal reciprocation of the piston.

Nonrotary piston for jackhammer and removable splined nut therefor

A variable frequency control for a hydraulic percussion actuator includes a piston bore and a valve bore. A piston is axially disposed within the piston bore, while a valve is axially disposed within the valve bore. A first piston biasing member biases the piston in a first direction while a second piston biasing member, which overcomes the bias of the first piston biasing member to move the piston in a second direction. A first valve biasing pin biases the valve in a third direction while a second valve biasing pin overcomes the bias of the first valve biasing pin to move the valve in a fourth direction. A hydraulic valve actuator displaces the second valve biasing pin when the piston is extended in the second direction, and a piston actuator activates the second piston biasing pin when the valve is extended in the fourth direction. A valve response member controls the time required for the valve to be displaced in said fourth direction upon actuation of said valve actuating member.

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Roanoke, VA, United States of America

Paul B Campbell