Pneumatically operated stapler with improved actuating and clinching mechanism

A pneumatically actuated fastener driving device comprising

• a housing defining a pressure chamber and a drive track,
• a piston mounted in said pressure chamber for movement through a pressure actuated drive stroke and a return stroke,
• a fastener driving element mounted in said drive track and operatively connected with said piston for movement therewith through a drive stroke and a return stroke,
• a valve member mounted on said housing for movement from a normal position into a firing position for enabling said piston to be moved through a pressure activated drive stroke and from its firing position into its normal position for enabling said piston to be moved through a return stroke,
• a trigger member mounted on said housing for pivotal movement between a normal position and a cocked position,
• an actuating member mounted on said trigger member for movement therewith and for controlled movement with respect to said trigger member,
• a control member mounted on said housing for movement between a control position and a release position,
• first interengaging means acting between said control member and said actuating member for enabling said control member (1) when in its control position to control the relative movement of said actuating member with respect to said trigger member so that the actuating member will be moved with the trigger member through a valve actuating movement in response to the movement of said trigger from said normal position into said cocked position and (2) when moved into its release position to control the relative movement of said actuating member with respect to said trigger member so that said actuating member will be enabled to move through a valve releasing movement following its valve actuating movement, while said trigger member is maintained in said cocked position,
• second interengaging means acting between said actuating member and said valve member for enabling said valve member (1) to move from its normal position into its firing position in response to the valve actuating movement of said actuating member and (2) from its firing position into its normal position in response to the valve releasing movement of said actuating member, and
• means for moving said control member from its control position to its release position in response to the movement of said fastener driving element through the end portion of its drive stroke.