SUMMARY OF THE INVENTION

The invention contains apparatus claims for a jarring apparatus comprising a cylindrical housing with hammer means for jarring an object in a well. A mandrel is slidably disposed within the housing to form a spring chamber. Also, the mandrel contains an anvil for receiving the impact from the hammer means.

The apparatus also contains latch means for latching the mandrel to the cylindrical housing. Biasing means are included for biasing the latch means in an engaged position within the housing. In one embodiment, the biasing means comprises frusto-conical disc springs capable of storing kinetic energy. The mandrel will have contained thereon a first and second releasing means for releasing the latch means thereby allowing the hammer to deliver an upper impact force to the anvil.

The mandrel will contain, in one embodiment, an internal and external shoulder. The anvil means, contained on the mandrel, will therefore comprise the external shoulder of the mandrel adapter to receive a downward impact from the hammer means. The anvil means further comprises the internal shoulder which is adapted to receive the hammer means for an upward jarring impact from the hammer means.

In one embodiment, the housing will contain an external and internal shoulder formed thereon. The hammer means, contained on the cylindrical housing, will therefore comprise the external shoulder of the housing adapted to downwardly impact the external shoulder of the mandrel, as well as the internal shoulder of the housing adapted to upwardly impact the internal shoulder of the mandrel.

The latch means will include in one embodiment, a plurality of latch bars, with the latch bars containing a first and second end, and a protuberance thereon, with the protuberance cooperating with the releasing means. The latch means also includes an upper ring for receiving the first end of the latch bar, and a lower ring for receiving the second end of the latch bar.

The latch bars are generally an elongated member with a first end and a second end, with the first end cooperating with the upper ring, and the second end cooperating with lower ring. The protuberance will have a first and second chamfered side.

The upper and lower ring contains a generally cylindrical member having a first end and second end, with the first end engaging the biasing means and the second end having an angled end with a leg member extending therefrom, with the angled end cooperating with said first end of the elongated member.

The automatic set bi-directional jar may also contain a biasing adjustment means, positioned within the housing, for adjusting the variable tension of the biasing means.

In the preferred embodiment, the distance from the first releasing means to the second releasing means is the length of the stroke of the jar. Also, the mandrel is tapered between the first releasing means to the second releasing means so that the latching means may expand as the housing is in motion during a jarring process. This allows free and unrestricted movement of the housing during the jarring operation.

A feature of the present invention includes the upper and lower releasing means which are contained on the mandrel. Another feature is that the housing means contains the hammer which allows for the housing to serve as the traveling mass which ultimately strikes the stationary anvil.

Another feature includes use of the inner mandrel as the stationary anvil means, with the mandrel being connected to the stuck object in the well bore. Still another feature includes the tapered mandrel which allows for the latch means to expand as the as the latch means travels with the hammer during jarring operation.

An advantage of the present invention is that immediately upon jarring, the apparatus is reset and will be able to impact in a reciprocal direction. Another advantage is that the apparatus jars in a sequential pattern, in that the apparatus will impact up, then down, and so on. Yet another advantage is that the jar is particular suited for use in deep and highly deviated well bores.