Torque responsive motor shutoff mechanism for fluid operated tool

In a fluid operated tool:

• a housing;
• a fluid operated motor disposed in said housing for driving a fastener engaging member;
• passage means in said housing for conducting pressure fluid to said motor;
• an operator actuated motive fluid supply valve interposed in said passage means;
• a torque sensing mechanism drivenly connected to said motor;
• and,
• a motive fluid shutoff valve interposed in said passage means between said supply valve and said motor, and operable to be in a valve closed condition to prevent flow of motive fluid to said motor and a valve open condition to permit flow of motive fluid to said motor when said supply valve is opened, said shutoff valve including a movable closure member and a movable seat;
• means interconnecting said closure member and said torque sensing mechanism for holding said closure member in a first closure member position and for allowing said closure member to move to a second closure member position in response to a predetermined torque exerted on said torque sensing mechanism,
• said seat including means for moving said seat to a first seat position in response to the admission of pressure fluid to said passage means to permit the flow of pressure fluid to said motor when said closure member is in said first closure member position, said closure member being operable in response to a predetermined torque exerted on said torque sensing mechanism to move to said second closure member position to engage said seat to shut off motive fluid flow to said motor, and means for causing said seat to move said closure member to said first closure member position upon closure of said supply valve.