Patent ID: 7325627
Filing Date: 2008-02-05
Classification: B25F

Abstract:
1. An air tool comprising: an air motor mechanism portion, for generating a rotational force by the compressed air, having an air supply port and an exhaust port of compressed air; an exhaust chamber, for discharging the compressed air exhausted from the exhaust port of the air motor mechanism portion to the atmosphere, having an exhaust hole communicating with the atmosphere at a portion of the exhaust chamber; an air joint portion connectable to a high pressure air supply source; a pressure reducing valve mechanism portion including a primary pressure side port connected to a side of the air joint portion, a secondary pressure side port connected to the air supply port of the air motor mechanism portion, an opening/closing valve arranged between the primary pressure side port and the secondary pressure side port for opening/closing a flow path of the compressed air flowing from the primary pressure side port to the secondary pressure side port, a pressure control spring for generating an urge force in a direction of opening the opening/closing valve, a closing direction pressure receiving face for receiving the compressed air operated in a direction of closing the opening/closing valve, and an opening direction pressure receiving face for receiving the compressed air operated to the opening/closing valve in a direction the same as the direction of the urge force of the pressure control spring; and a trigger valve mechanism portion including a valve member for opening/closing a flow path between the secondary pressure side port of the pressure reducing valve mechanism portion and the air supply port of the air motor mechanism portion, a trigger for controlling to open/close the valve member, and a pressing member for pressing in a direction reverse to a direction of operating the trigger for opening the valve member in correspondence with an amount of operating the trigger to drive the air motor mechanism portion; wherein when the air motor mechanism portion is driven by opening the valve member by operating the trigger of the trigger valve mechanism portion, a pressure of air exhausted from the exhaust port of the air motor mechanism portion to the exhaust chamber is added to the urge force of the pressure control spring by being received by the opening direction pressure receiving face of the pressure reducing valve mechanism portion.