LATCH-PIN TRIPPING MECHANISM FOR USE IN ASSOCIATION WITH A MECHANICAL DRILLING JAR

摘要

The specification describes an improved latching assembly for use in a mechanical drilling jar. The latching assemblies currently in use are subject to wear through friction when in the unlatched position as maximum pressure is on the latch at that point and also when in the latched position due to axial movement caused by the positioning of the latch assembly between sets of springs. The latching assembly described in the specification reduces wear in the unlatched position as maximum pressure is placed on the latch assembly when in the latched position. This is accomplished by using a split collet with a profile on its face as a means of engaging an accommodating profile on a latching seat of the inner mandrel. Latch pins are used to move the split collet off the latching seat when a preset plateau of tension or compression is reached. Axial movement is eliminated by having the latch assembly held against a shoulder on the outer housing by a single set of springs.