Abstract: There is disclosed a double acting hydraulic jar of such construction as to permit it to be "short cocked" during either an up or down jar, and further in which flow past a detent in metered in such a way as to permit lesser flow therepast during an upward jar than during a downward jar, whereby the rate of movement of the detent ring through a restriction, and thus the "delay", may be essentially the same during both up and down jars.

Abstract: A drilling jar is disclosed. The jar has particular application in directional drilling operations and includes a swivel which allows the drilling jar to operate substantially independently of any right hand torque that becomes trapped in the drill string. The swivel includes a bearing cage that engages the polished stem of the drilling jar to the jay stem of the drilling jar. This bearing cage holds a number of bearings against the jay stem and the polished stem. The swivel allows the jay stem to rotate substantially independently of the polished stem. The drilling jar may further include splines formed onto the outer surface of the polished stem for transmitting torque from the polished stem to the barrel of the drilling jar without simultaneously transmitting torque from the polished stem to the jay stem.

Abstract: The present invention includes a tubular body member with a central bore which has two spiralling or threaded interior surfaces, each interior surface having a leading edge at nearly right angles to the longitudinal axis of the body and a sloped or tapered trailing edge along the bore from an end portion toward the central portion of the bore. The upper portion of the body has a left-hand spiralling or threaded surface. The lower portion of the body has a right-hand spiralling or threaded surface. Inserted into the central portion of the body member from each end is a slip segment or member. The outer surface of the upper slip segment has a left-hand spiralling or threaded surface, whereas the outer surface of the lower slip segment has a right-hand spiralling or threaded surface. Each such spiralling or threaded surface conforms to the spiralling or threaded surface of the corresponding interior surface of the stabilizer body.

Abstract: A well tool carried in a drill string for maintaining bottom hole contact while absorbing angular and axial shock forces of a rotating drill bit. The tool has an elongated body with pipe joint ends and includes a tubular mandrel slideably mounted within a tubular barrel. A groove and roller connection guides the mandrel within the barrel during drilling. Resilient shock absorbing members between metal guide rings are carried between stop elements on the mandrel and barrel. Shock forces are absorbed by the telescoping movements of the mandrel within the barrel and by in the members acted on by the stop elements. The mandrel is formed of two pieces that threadedly connect to one another between the resilient shock absorbing members and the groove and roller connection. A lifting lug positioned above the rollers and below the shock absorbing members within an elongate mandrel groove, engages the joint to transfer the weight of the mandrel to the barrel upon withdrawal of the tool.

Abstract: For use in a well jar, a mounting apparatus for resilient elongate snubbers is described. In the preferred and illustrated embodiment, parallel elongate resilient snubbers are formed on metallic backing strips. They are profiled to define sloping elongate sides which slidably fit within undercut grooves. The undercut grooves extend from an encircling shoulder to enable easy insertion into the grooves. The shoulder is adjacent to an encircling narrow neck, thereby enabling an expandable lock ring to be positioned in the neck, securing the resilient snubbers in position.

Abstract: A well tool carried in a drill string for maintaining bottom hole contact while absorbing angular and axial shock forces of a rotating drill bit. The tool has an elongated body with pipe joint ends and includes a tubular mandrel rotationally and slideably mounted within a tubular barrel. A groove (preferably helical) and roller connection guides the mandrel from the barrel during drilling. Resilient shock absorbing members between metal guide rings are carried between stop elements on the mandrel and barrel. Shock forces are absorbed initially by the rotating/telescoping movements of the mandrel within the barrel. Excess shock forces are absorbed in the members acted on by the stop elements on further inward/outward movements of the mandrel rotating in the barrel. Unique cross-over rings (graphite-filled Teflon.RTM.) cushion the resilient members from impacts of the metal guide rings.