Abstract: An overshot tool for releasable connection to a head assembly as part of a core barrel drilling apparatus. The overshot tool comprises a primary engaging portion and a secondary engaging portion and is configured for the automated coupling and de-coupling to a head assembly via selected engagement of the head assembly by the engaging portion. The overshot tool is configured to both deliver and retrieve a head assembly from a latched position at a cutting end the core barrel.

Abstract: An inner tube assembly releasably latchable with a core barrel of a core drilling apparatus. The inner tube assembly includes a valve housing having a fluid flow port and a position guide to control a position of the valve body within the valve housing to open and close the port in response to a fluid pressure acting on the valve body.

Abstract: A lockable overshot assembly for use in a wireline spearhead system for lowering and retrieving inner tube assemblies and other tools and equipment from a downhole location includes a pair of lifting dogs pivotally mounted to an overshot head on the lockable overshot assembly and configured for latching a spearhead. A locking arrangement is mounted into the elongated body and engagable within the lifting dogs, such that in a locked state the lifting dogs are in latched position and in an unlocked state, allows the lifting dogs to move to the release position. The locking arrangement is a pin, which can be moved laterally to be between the latching dogs to prevent them moving to the release position.

Abstract: A lockable overshot assembly for use in a wireline spearhead system for lowering and retrieving inner tube assemblies and other tools and equipment from a downhole location includes a pair of lifting dogs pivotally mounted to an overshot head on the lockable overshot assembly and configured for latching a spearhead. A locking arrangement is mounted into the elongated body and engagable within the lifting dogs, such that in a locked state the lifting dogs are in latched position and in an unlocked state, allows the lifting dogs to move to the release position. The locking arrangement is a pin, which can be moved laterally to be between the latching dogs to prevent them moving to the release position.

Abstract: An overshot tool for releasable connection to a head assembly as part of a core barrel drilling apparatus. The overshot tool comprises a primary engaging portion and a secondary engaging portion and is configured for the automated coupling and de-coupling to a head assembly via selected engagement of the head assembly by the engaging portion. The overshot tool is configured to both deliver and retrieve a head assembly from a latched position at a cutting end the core barrel.

Abstract: An inner tube assembly releasably latchable with a core barrel of a core drilling apparatus. The inner tube assembly includes a valve housing having a fluid flow port and a position guide to control a position of the valve body within the valve housing to open and close the port in response to a fluid pressure acting on the valve body.

Abstract: A member of a joint for a thin-walled drill tube presents a central axis and has a thread for forming a screw joint. The thread presents a thread bottom, a thread top, a pressure flank and a clearance flank. The pressure flank presents a portion having a negative angle less than 7.5°, but at least 0°, relative to a direction perpendicular to the central axis.

Abstract: A member of a joint for a thin-walled drill tube presents a central axis and comprises a thread for forming a screw joint. The thread presents a thread bottom, a thread top, a pressure flank and a clearance flank. The pressure flank presents a portion having a negative angle less than 7.5°, but at least 0°, relative to a direction perpendicular to the central axis.