EP 0083961 A2 19830720 - Improved jar tool for drill strings.
Title (en)
Improved jar tool for drill strings.
Title (de)
Schlagschieber für Bohrgestänge.
Title (fr)
Coulisses de battage pour tiges de forage.
Publication
Application
Priority
CA 393583 A 19820106
Abstract (en)
A jar tool for use in a drill string for use in dislodging a drill bit or well-tools trapped in well bores. The tool comprises an outer housing adapted to move longitudinally with respect to an inner spline mandrell. A piston assembly is acted on by a piston actuator and hydraulic fluid restricts the movement of the piston assembly and, therefore, the movement of the mandrell relative to the housing while the piston assembly is within a narrower portion of a hydraulic cylinder. When the piston assembly reaches a larger diameter portion of the cylinder, the hydraulic fluid rushes past the piston assembly which allows a knocker connected to the spline mandrell to collide with the outer housing. A compression spring returns the piston assembly to its rest position abutting a shoulder on the outer housing. Provision is made for a valve to be inserted in the piston assembly so that the system can be temperature compensated and more desirable hydraulic fluids can be used.
IPC 1-7
IPC 8 full level
E21B 31/113 (2006.01)
CPC (source: EP)
E21B 31/113 (2013.01)
Designated contracting state (EPC)
AT BE DE FR GB NL SE
DOCDB simple family (publication)
EP 0083961 A2 19830720; EP 0083961 A3 19840725; CA 1177058 A 19841030
DOCDB simple family (application)
EP 83300016 A 19830105; CA 393583 A 19820106