U.S. Patent No. 7,367,397 - Downhole Impact Generator And Method For Use Of Same (May 6, 2008)

A downhole impact generator (60) is adapted to be moved to a target location within a wellbore (68) for transmitting a jarring force to a well tool (72) positioned in the wellbore (68). The downhole impact generator (60) includes a downhole power unit (62) having a moveable shaft (66) and a jarring tool (64). The jarring tool (64) is operably engageable with the well tool (72) and is operably coupled with the moveable shaft (66) of the downhole power unit (62) such that when the jarring tool (64) is operably engaged with the well tool (72), linear movement of the moveable shaft (66) energizes the jarring tool (64) such that a jarring force can be transmitted by the jarring tool (64) to the well tool (72).