Patent ID: 7029253

Claim:
A pneumatic cylinder of a pneumatic tool comprising: a) a cylinder body having: i) an cylindrical chamber; ii) an inlet located in the in a wall thereof and communicating with the cylindrical chamber; and iii) a predetermined number of outlets communicating with the cylindrical chamber; b) two end caps, one of the two end caps is located on each of two opposing ends of the cylindrical body, each of the two end caps having: i) a first central through hole; ii) an annular projecting wall; and iii) a circular cavity extending through the annular projecting wall and communicating with the first central through hole, the circular cavity having a circular dent located in a bottom thereof; c) a rotor located in the cylindrical chamber and having a rotary shaft being fixed thereto, one of two ends of the rotary shaft being inserted through the first central through hole of each of the two end caps; d) two bearings, one of the two bearings being located in the circular cavity of each of the two end caps; and e) two airtight rings, one of the two airtight rings being located in each circular dent between one of the two bearings and the bottom of the circular cavity of each of the two end caps, each of the two airtight rings having a second central through hole, one of two ends of the rotary shaft being inserted through the second central through hole of each of the two airtight rings.