Oil pressure type impulse torque generator for wrench

Claim 1

An impulse wrench, comprising: a housing; a liner rotatably mounted within said housing and having a longitudinal axis and a cavity of elliptical cross-section extending along said axis, an inner peripheral surface of said cavity having a first pair of liner seals extending in the direction of said longitudinal axis and disposed in opposed relation on a first axis line perpendicular to said longitudinal axis, and a second pair of liner seals extending in the direction of said longitudinal axis and disposed on said surface in substantially opposed relation on a second axis line perpendicular to both said longitudinal axis and said first axis line, and containing said axis line; means for rotating said liner about said longitudinal axis; a main shaft disposed within said cavity coaxially to said longitudinal axis, an outer peripheral surface of said shaft having a first pair of shaft seals extending in the direction of said longitudinal axis and disposed in opposed relation to a first shaft line perpendicular to said longitudinal axis, and a pair of blade grooves extending in the direction of said longitudinal axis and disposed on a second shaft line perpendicular to both said longitudinal axis and said first shaft line, and containing said longitudinal axis, said main shaft including a blade mounted within each of said blade grooves, each of said blades being biased outwardly from said main shaft substantially along said second shaft line and including an outer face, and said main shaft further including a roller mounted in said outer face of each of said blades, each said roller being mounted for rotation about an axis substantially parallel to said longitudinal axis, whereby said rollers form a second pair of shaft seals, said first shaft seals and said first liner seals being adapted to cooperate to form fluid seals, and said second shaft seals and said liner seals being adapted to cooperate to form fluid seals.