Patent ID: 7510008

Claim:
A jar, comprising: a cylindrical body having an anvil therein; a mandrel concentric inside the cylindrical body, the mandrel having a set of grooves at a selected position and a hammer; a trigger sleeve disposed inside the cylindrical body, the trigger sleeve having grooves and protuberances in an inside diameter; a collet disposed between the trigger sleeve and the mandrel, the collet having grooves and protuberances in an inside diameter adapted to come into registration with the grooves of the mandrel and grooves and protuberances on an outside diameter adapted to come into registration with the trigger sleeve; a main spring in the cylindrical body disposed to apply a first axial force to the collet as the collet moves a selected displacement to compress the main spring until the grooves and protuberances on the outside diameter of the collet come into registration with the grooves and protuberances in the outside diameter of the trigger sleeve to release the mandrel; a shoulder disposed to relieve the first axial force to the collet after the mandrel is released; an auxiliary spring in the cylindrical body disposed to apply a second axial force to the trigger sleeve and the collet after the mandrel is released, the second axial force being less than the first axial force.