Patent ID: 6905401

Claim:
A bi-directional rotation pneumatic grinding tool for surface grinding operation comprising an operating section and a handgrip, wherein the operating section includes: an actuator to drive a transmission axle to rotate in two directions, the transmission axle having a spline section and a screw hole formed in the spline section; a coupling member which has through openings on two ends, one end having a coupling section which has a first splined trough formed therein to couple with the spline section of the transmission axle; a fastening member which has through openings on two ends, one end having a second splined trough formed on an inner wall and being insertable into the coupling member to couple with the spline section of the transmission axle; and a fastening element which has screw threads formed thereon to run through the fastening member to fasten to the screw hole of the transmission axle; wherein forming and coupling of the spline section and the first splined trough and the second splined trough allows the transmission axle to rotate in a positive direction or an inverse direction as desired without loosening off and facilitates fabrication and assembly without concerning screw thread direction and sparks, grinding debris or dusts generated during grinding operation are allowed to be directed in a desired direction without polluting working environments or hurting people or damaging work pieces.