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U.S. Department of Energy
Office of Scientific and Technical Information

Mechanical down jar mechanism

Patent ·
OSTI ID:5666906
This paper describes a mechanical down jar mechanism for freeing stuck objects within a well bore and for conducting other down hole activities. It comprises: an elongate tubular housing having anvil means; mandrel means adapted for connection to an object to be moved downwardly within the well bore and being disposed in telescoping relation with the anvil means and the elongate tubular housing, the mandrel means adapted to be struck by the anvil means to impart a downwardly directed jarring force to the object; the elongate tubular housing having internal firing and recocking detent groove means located in axially spaced relation and forming a firing lug support land therebetween; a radially expandable and retractable firing lug assembly being disposed within the elongate tubular housing and in absence of force being applied axially thereto being radially restrained by the firing lug support land; load spring means being disposed within the elongate tubular housing and being in downward force transmitting relation with the firing lug assembly; recocking spring means being disposed within the elongate tubular housing and having upward axial force transmitting relation with the firing lug assembly.
Assignee:
NOV; NOV-92-021419; EDB-92-085771
Patent Number(s):
A; US 5069282
Application Number:
PPN: US 7-625113
OSTI ID:
5666906
Country of Publication:
United States
Language:
English