Patent attributes
A jarring apparatus includes first and second jarring assemblies rotatable relative to each other. A first impact surface is provided on the first jarring assembly and a second impact surface is provided on the second jarring assembly, wherein, in use, the first and second impact surfaces are biased together. A first lifting structure is rotatably fixed relative to the first jarring assembly and a second lifting structure is rotatably fixed relative to the second jarring assembly, the first and second lifting structures being configured to cooperate during relative rotation therebetween to cause cyclical relative displacement in one axial direction to define a lifting phase and relative displacement in a reverse axial direction to define a dropping phase. The first and second lifting structures are axially fixed relative to their associated jarring assembly during the lifting phase to provide axial separation between the first and second impact surfaces, and the second lifting structure is axially released relative to the second jarring assembly prior to initiation of the dropping phase to permit the first and second impact surfaces to be axially impacted together.
