简介:-Thispapercarriesouttheanalysisofmechanicsofagripsystemofthree-key-boardhydraulictongsdevelopedforoffshoreoilpipelineswhichhasbeensuccessfullyusedinoilfieldsinChina.Themainimprovementofthissystemisthataleverframestructureisusedinthestructuraldesign,whichreducesgreatlythestressesofthemajorcomponentsoftheoilpipetongs.Theoreticalanalysisandnumericalcalcu-lationbasedonthirteenbasicequationsdevelopedshowthattheteethboardofthetongsisnoteasytoslipasfrequentlyhappenstoothersystemsandisofhigherreliability.