초록 ▼

A pneumatic fastener applying tool featuring a self-cycling control valve with one moving port. A trigger actuated valve sets the cycling valve in motion. The cycling valve alternatively pressurizes and vents the working piston of the fastener tool. A valve stem is positioned by an integral reciproc

A pneumatic fastener applying tool featuring a self-cycling control valve with one moving port. A trigger actuated valve sets the cycling valve in motion. The cycling valve alternatively pressurizes and vents the working piston of the fastener tool. A valve stem is positioned by an integral reciprocating piston. The position of the reciprocating piston is determined by the balance of forces between a biasing spring tending to vent the working piston and a pressure-force tending to pressurize the working piston. Two flow paths, internal to the valve stem, determine the pressure applied to the reciprocating piston. One path pressurizes the reciprocating piston. Another path vents the reciprocating piston. Positive feedback of air pressure from the working cylinder positions the reciprocating piston and valve stem so as to vent the reciprocating piston when the working piston is vented and to pressurize the reciprocating piston when the working piston is pressurized. Releasing the trigger actuated valve holds the cycling valve in place and prevents further operation of the fastener tool.

대표청구항 ▼

In a fastener applying device having a housing joined to a supply of fluid under pressure and including a working cylinder having a fastener driver means reciprocable therein in a cycle including one working and one return stroke, a first means for biasing said fastener driver means to the end of sa

In a fastener applying device having a housing joined to a supply of fluid under pressure and including a working cylinder having a fastener driver means reciprocable therein in a cycle including one working and one return stroke, a first means for biasing said fastener driver means to the end of said return stroke, a means for feeding a fastener into position to be driven after each return stroke of said fastener driver means, a main valve means for controlling the flow of said fluid under pressure into said working cylinder above said fastener driver means and, an exhaust valve means for venting to atmosphere that portion of said working cylinder above said fastener driver means, an improved control structure comprising: (a) a control cylinder having one end closed and one end opened to said supply of fluid pressure in said housing; (b) a control piston movable within said control cylinder from a first position to a second position effective to open said main valve means and to close said exhaust means, said control piston being integral to said main valve means, said control piston and the closed end of said control cylinder defining a control chamber, the first side of said control piston being defined as that side of said control piston continuously exposed to the air pressure in said housing, said housing pressure thus biasing said control piston to said second position; (c) a first flow means in said control piston for effecting flow communication between said control chamber and said supply of fluid under pressure; (d) a second flow means in said control piston for effecting flow communication between said control chamber and the atmosphere; (e) means responsive to the pressure above said fastener driver means for sequentially closing said second flow means and opening said first flow means, and closing said first flow means and opening said second flow means to the effect that said control piston is cycled between said first and said second positions with said fastener driver means being cycled through said working and return strokes in response thereto.