Abstract: A mechanical well jar is disclosed having inner and outer tubular members movable longitudinally relative to each other a limited distance for connecting in a pipe string. Annular shoulders on the members engage to limit the relative longitudinal movement of the members. A plurality of laterally spaced, arcuate cam plates are attached to the inner surface of the outer member. Each plate has a laterally extending U-shaped notch opening into the space between the plates and formed with curved outwardly flaring sidewalls. Rollers are mounted on the outer surface of the inner member to extend into the spaces between the cam plates for movement into the U-shaped notches to hold the members from longitudinal movement relative to each other.

Abstract: A wire line anchor has a slot in its side wall that will move the slot into position to engage a key attached to a housing in a pipe string to hold the anchor against upward movement relative to the housing. The anchor is released from the key by subsequent downward movement followed by upward movement of the anchor relative to the key.

Abstract: A dump valve having a valve seat and a valve member is located in a string of drill pipe above a downhole motor. The dump valve connects the inside of the drill string with the annulus and allows drilling mud to flow freely therebetween when drilling mud is not being pumped through the drill string to operate the downhole motor. The valve member is made of a deformable resilient material such as rubber. It is held away from the valve seat by spacers until the pressure drop across the valve member is sufficient to deform the valve member and move it past the spacers into engagement with the valve seat. When the pressure differential is relieved, the valve member will return to its normal, unstressed shape opening the valve.

Abstract: A stator is disclosed for use with down-hole fluid powered drilling motors of the Moineau type. It includes a housing and a plurality of removable stator sections positioned in end-to-end, abutting relationship in the housing. Each section comprises a cylindrical body of elastomeric material having an obround opening extending longitudinally therethrough. The opening spirals along a helical path with a pitch equal to the length of the section. A method is disclosed for positioning a plurality of the sections in a statorhousing in end-to-end, abutting relationship with the opening properly oriented to form a continuous helical opening through the stator to receive a helically shaped rotor having one half the pitch of the helical opening. Each section includes a cylindrical reinforcing member embedded in the body of elastomeric material. An annular portion of the body has an outside diameter greater than the inside diameter of the housing.

Abstract: A bearing is disclosed that includes a support housing or casing in which is located a body of elastomeric material. A plurality of wear members are positioned to be supported by the body of elastomeric material and to receive the load placed on the bearing. The elastomeric body allows the wear inserts to adjust individually to the load placed on the wear members, which greatly increases the life of the bearing. The wear members are made of a self-lubricating type material, such as one of the fluorocarbons or polyphenylene sulfide resin.

Abstract: Apparatus is disclosed to indicate at the surface when a tool lowered into a well bore on an electric cable is properly positioned in a downhole housing. The tool has a key slot and a muleshoe is carried by the tool to engage a key located on the housing and to guide the key into the key slot to properly position the tool. A sensing coil is carried by the tool and positioned for its magnetic field to pass through the key slot. Circuit means monitor the magnetic field and indicate at the surface when the key has been properly positioned in the slot.

Abstract: Method and apparatus to lift the rotor of an earth borehole downhole drilling motor with a resilient force that exceeds the rotor weight so that starting of the motor is more certain due to reduced drag on primary thrust bearings. Additionally the apparatus may be used to reduce imbalanced axial loads on rotor primary thrust bearings.

Abstract: A stabilizer is disclosed that can be mounted on the outside of the drill string. It includes a tubular body having a bore to receive the drill string to allow the body to be moved over the drill string to the desired location. A portion of the bore has a locking taper in which is located a plurality of slip fingers. A sleeve member is connected to the body by threads and is in engagement with the slip fingers. Relative rotation of the sleeve and the body will cause the sleeve to force the slip fingers along the tapered bore of the body and into frictional engagement with the outside surface of the drill string to hold the stabilizer in the desired location thereon.