US 4,054,180 AGranted

Impact drilling tool having a shuttle valve

AssigneeReed Tool Company

InventorGrey Bassinger

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Abstract

An impact drilling tool for rotary drilling which includes a reciprocating hammer inside a casing for striking the top of an anvil. A drilling bit is connected to the opposite end of the anvil for cutting into the earth's formations. The casing is connected in a string of drilling pipe through which a high pressure fluid flows for operating the hammer and removing cuttings. A feeder means extends through the hammer for alternately directing the high pressure fluid above and below the hammer which high pressure fluid causes the reciprocating motion of the hammer. A shuttle valve located around the feeder maintains communication of the high pressure fluid above the hammer for increased effective stroke to insure a harder driving action of the hammer against the anvil. Also the shuttle valve insures a more complete exhaust above the hammer which reduces the force needed to raise the hammer. In alternative embodiments, the shuttle may control only one of the exhaust or pressurization functions.

Claims17

Dependent claims

In an impact drilling tool for operation by high pressure fluid comprising a casing, an upper sub connected to said casing for connection to a string of drilling pipe, anvil means slidably positioned in a lower end of said casing, bit means located below said anvil means, hammer means slidably positioned in said casing for periodically impacting said anvil means, feeder means in said casing extending downward into an opening of said hammer means adapted to receive high pressure fluid from said drillng pipe, upper cross passages in said feeder means periodically communicating said high pressure fluid from a center flow passage through said hammer means to an upper pressure chamber, lower cross passages in said feeder means periodically communicating said high pressure fluid from said center flow passage through said hammer means to a lower pressure chamber, the improvement comprising:

shuttle valve means surrounding said upper cross passage of said feeder means, said shuttle valve means having shuttle passages therethrough maintaining communication with said upper cross passages, said shuttle valve means being movable along said feeder means between a first and second position to provide periodic communication between the shuttle passages and the upper pressure chamber, and said shuttle valve means being movable preceding like movement of said hammer means, with communication through said upper cross passage with said upper pressure chamber being maintained through said shuttle passages for a substantially extended portion of a downstroke of said hammer means.

A feeder for an impact drilling tool for controlling flow of a high pressure fluid to an upper pressure chamber above a hammer and a lower pressure chamber below the hammer, said feeder being adapted to be positioned inside an opening of said hammer with upper hammer passages communicating between said opening and said upper pressure chamber and lower hammer passage communicating between said opening and said lower pressure chamber, said feeder comprising,

an elongated body portion having a center flow passage therethrough for receiving said high pressure fluid;
a shuttle valve surrounding said feeder;
upper cross passages for communicating between said center flow passage and said shuttle valve;
lower cross passages for communicating between said center flow passage and said lower pressure chamber via said lower hammer passage when said hammer is in its lower position;
said shuttle valve having an upper surface and a lower surface for slidably between said feeder and said hammer, shuttle passages between said upper and lower surface for periodically communicating said high pressure fluid from said upper cross passages to said upper pressure chamber via said upper hammer passages, and said upper and lower surfaces being of a size and shape such that application of high pressure fluid thereto moves said shuttle valve to an up position and down position faster than said hammer moves up and down.

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Dependencies are inferred from the claim text.