The double acting mechanical-hydraulic drilling jar type jyq is designed for drilling operation to apply an intensified force either up or down against a stuck portion of the drilling string. It incorporates the feature of both hydraulic and mechanical drilling jars, without of the inherent disadvantage of either type. Its unique design combines both a hydraulic time delay release and mechanical latch mechanism in one relatively short,double acting drilling jar. Type JYQ121 JYQ121II JYQ159 JYQ165 JYQ189 JYQ203 JYQ241 OD mm 124~241 ID mm 50.8~76.2 Up Stroke mm 227~232 Down Stroke mm 102~152 Working Torque kN.m 12.5~50 Max Tensile load kN 1300~5400 Max up Jarring kN 250~1400 Max down Jarring kN 200~460 Overall Length mm 1500~5300 Piston areas mm2 2516~17200