Wells – With jar means for releasing stuck part
Reexamination Certificate
2005-09-27
2005-09-27
Dang, Hoang (Department: 3672)
Wells
With jar means for releasing stuck part
C175S302000, C175S304000
Reexamination Certificate
active
06948560
ABSTRACT:
A jar (10), for use in a downhole toolstring comprising: a hollow housing (11); a jar mandrel (13); a latch sub (14); one or more latch keys (16); a cam surface (17); a chamber (23); a compression spring; and an adjuster (24). The hollow housing (11) supports, moveably retained therein, the jar mandrel (13). The jar mandrel (13) and the latch sub (14) are releasably securable together by means of the one or more latch keys (16), and each latch key (16) is moveable between a latching position, in which the latching sub (14) and the jar mandrel (13) are connected together, and a release position permitting separation thereof. The cam surface (17) engages each latch key (16) to move it from its latching position to its release position when the jar mandrel (13) occupies a preselected position in the housing (11). The compression spring (24) is constrained within the chamber (23) and acts between the latch sub (14) and the hollow housing (11) to bias the jar mandrel (13) when connected to the latch sub (14) away from the predetermined position; and the adjuster (27) includes an adjuster mandrel (47) that is rotatable relative to the hollow housing and has an external portion (49) that is engageable from outside the hollow housing (11) via a side thereof. An adjuster portion (51) is threadedly connected to the jar mandrel (13) such that rotation of the adjuster mandrel (47) relative to the jar mandrel (13) alters the length of the chamber (23) and hence the degree of compression of the compression spring (24).
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Dang Hoang
Finnegan Henderson Farabow Garrett & Dunner LLP
Varco I/P Inc.
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