Patent ID: 7497363

Claim:
A pneumatic fixing machine comprising: a piston means ( 30 ) slidably located inside a cylinder ( 33 ); first valve means ( 5 ) movable between two extreme positions, an opening position (E), such that the first valve means are in fluidic communication with an inlet portion ( 33 a ) of said cylinder ( 33 ) for receiving a pressurized fluid and a closing position (D) where the first valve means are in communication with an external outlet; second valve means ( 2 ) movable in response to operation of a trigger ( 7 ), the second valve means movable between an occlusion position (M) for fluidly connecting at least a first duct ( 9 ) and a base portion ( 5 a ) of the first valve means ( 5 ) for feeding the pressurized fluid therethrough, and, a passage position (L) for connecting to an external outlet; third valve means ( 3 ) movable between a position of obstruction (N), to cut off flow between the first duct ( 9 ) and the first valve means ( 5 ), and, a crossing position (Q), which opens a flow connection between the duct ( 9 ) and the first valve means ( 5 ); fourth valve means ( 4 ) movable in response to operation of the trigger ( 7 ), the fourth valve means movable between a block position (S), where flow is obstructed between the cylinder ( 33 ) and the third valve means ( 3 ), and, a transit position (T) such that flow is permitted between the cylinder ( 33 ) and the third valve means ( 3 ); the fourth valve means ( 4 ) being a lengthened and shaped element, slidably housed inside a first seat ( 12 ) which is complementary shaped and in fluid communication with the cylinder ( 30 ) through a second duct ( 16 ), the lengthened and shaped element protruding externally from the first seat ( 12 ), and having an element portion engageable by the trigger; and, elastic means ( 13 ) for exerting a biasing force on the fourth valve means ( 4 ) to bias the fourth means towards the block position (S), in absence of operation of the trigger ( 7 ); wherein in a first activation condition (A), the trigger ( 7 ) is partially pressed, positioning the second valve means ( 2 ) in the passage position (L), to allow the pressurized fluid to push the first valve means ( 5 ) into the opening position (L), actuating the piston means ( 30 ); and wherein in a second activation condition (B), the trigger ( 7 ) is further and completely pressed only after overcoming the biasing force of the elastic means ( 13 ) to give a tactile feel when the trigger engages the element portion and displaces the element, moving the fourth valve means ( 4 ) into the transit position (T), to allow the pressurized fluid coming from the cylinder ( 33 ) to move the third valve means ( 3 ) into the occlusion position (N), causing the return of the first valve means ( 5 ) to the closing position (D) and the consequent return of the piston means ( 30 ) to the initial position (F).