Abstract: A device has a first, lower sub housing, a second, upper sub housing, and an extensible joint connecting the lower sub housing to the upper sub housing. A pressure equalization chamber is attached to the upper sub housing and demarcates an inner zone including an internal mechanism of the extensible joint, and an outer zone open to well bore fluids and pressure. A fluid barrier moves within the pressure equalization chamber in response to changes in well bore pressure to alter a volume of the inner zone to equalize a pressure of the inner zone.

Abstract: A jarring tool is disclosed. The tool has a segment of sub housing containing an upper stop proximate a first end thereof. An outer latch piece is connected to an upper end of the lower shaft inside the sub housing, and an upper shaft passes through the stop and connects on a first end thereof to an inner latch piece. A cap is on a second end of the upper shaft retaining a washer stack against the upper stop. A retainer is inside the sub housing and has an first piece providing a restraining region and an open region and a second piece attached to the sub housing. The retainer retains the inner and outer latch pieces in a latched position in the restraining region until the latch pieces are displaced toward the second end of the sub housing through the retainer to the open region as a result of a tensile force on the outer latch piece.

Abstract: A device has a first, lower sub housing, a second, upper sub housing, and an extensible joint connecting the lower sub housing to the upper sub housing. A pressure equalization chamber is attached to the upper sub housing and demarcates an inner zone including an internal mechanism of the extensible joint, and an outer zone open to well bore fluids and pressure. A fluid barrier moves within the pressure equalization chamber in response to changes in well bore pressure to alter a volume of the inner zone to equalize a pressure of the inner zone.

Abstract: A jarring tool having an extensible joint connecting first and second sub ends. A first inner latch piece connects to the upper sub end, and a second outer latch piece connects to the lower sub end. The joint, in a latched position, has the outer latch piece latched to the inner latch piece and the inner and outer latch pieces restrained from unlatching by a stationary restraining collar. Under tensile force the joint unlatches into an unlatched position by the outer latch piece pulling the inner latch piece through the restraining collar into a position where the inner and outer latch pieces are free to separate. An impact force is generated from the tensile force when the joint unlatches and reaches a maximum extension.

Abstract: A tool having a first lower sub end, a second upper sub end, and an extensible joint connecting the first and second sub ends. The joint has a first inner latch piece connected to the lower sub end, and a second outer latch piece connected to the upper sub end, and a stationary restraining collar. The joint, in a latched position, has the outer latch piece latched to the inner latch piece and the inner and outer latch pieces restrained from unlatching by the restraining collar. The joint, under tensile force, unlatches into an unlatched position by the inner latch piece pulling the outer latch piece through the restraining collar into a position where the inner and outer latch pieces are free to separate. An impact force is generated from the tensile force when the joint unlatches and reaches a maximum extension.

Abstract: A tool having a first lower sub end, a second upper sub end, and an extensible joint connecting the first and second sub ends is disclosed. The joint has a first inner latch piece connected to the lower sub end, and a second outer latch piece connected to the upper sub end, and a stationary restraining collar. The joint, in a latched position, has the outer latch piece latched to the inner latch piece and the inner and outer latch pieces restrained from unlatching by the restraining collar. The joint, under tensile force, unlatches into an unlatched position by the inner latch piece pulling the outer latch piece through the restraining collar into a position where the inner and outer latch pieces are free to separate. An impact force is generated from the tensile force when the joint unlatches and reaches a maximum extension.

Abstract: A jarring tool having an extensible joint connecting first and second sub ends is disclosed. A first inner latch piece connects to the upper sub end, and a second outer latch piece connects to the lower sub end. The joint, in a latched position, has the outer latch piece latched to the inner latch piece and the inner and outer latch pieces restrained from unlatching by a stationary restraining collar. Under tensile force the joint unlatches into an unlatched position by the outer latch piece pulling the inner latch piece through the restraining collar into a position where the inner and outer latch pieces are free to separate. An impact force is generated from the tensile force when the joint unlatches and reaches a maximum extension.

Abstract: A jarring tool is disclosed. The tool has a segment of sub housing containing an upper stop proximate a first end thereof. An outer latch piece is connected to an upper end of the lower shaft inside the sub housing, and an upper shaft passes through the stop and connects on a first end thereof to an inner latch piece. A cap is on a second end of the upper shaft retaining a washer stack against the upper stop. A retainer is inside the sub housing and has an first piece providing a restraining region and an open region and a second piece attached to the sub housing. The retainer retains the inner and outer latch pieces in a latched position in the restraining region until the latch pieces are displaced toward the second end of the sub housing through the retainer to the open region as a result of a tensile force on the outer latch piece.