Patent ID: 6984169

Claim:
A bi-directional rotation pneumatic grinding tool comprising a body which has an operation section and a grasp section, the operation section having an actuator to drive an output shaft to rotate in two directions, the output shaft having positive threads formed on an inner wall thereof and reverse threads formed on an outer wall, and being coupled with a fastening mechanism, wherein the fastening mechanism includes: a coupling head which has two ends communicating with each other, one end forming a fastening section which has first reverse threads formed in the interior for fastening to the reverse threads of the output shaft and other end forming a connecting section; a connection member which has two ends communicating with each other and is located in the coupling head, one end thereof forming a latch section which has second reverse threads formed therein to couple with the reverse threads of the output shaft and other end forming an engaging section which has third reverse threads formed on an outer wall thereof; an anchor member which has two ends communicating with each other, one end thereof forming a coupling section which has fourth reverse threads to engage with the third reverse threads of the connection member; and a fastener which has positive threads formed thereon to run through the anchor member and engage with the positive threads of the output shaft, the fastener being entirely encased in the fastening mechanism; wherein the positive threads and the reverse threads are engageable with one other to allow the pneumatic grinding tool to rotate in a positive direction or a reverse direction according to different requirements without loosening and direct sparks, grinding debris or dusts generated in grinding processes in a desired direction without polluting environment or hurting people and working pieces.