Air chuck

Claim 1

In an air chuck molded of synthetic resin material comprising a body having a main portion and a head portion, said main portion having an end face constituting a back face, said head portion having an end face constituting a front face, an axial bore constituting an inlet bore extending into said main portion from said back face, one end of said inlet bore being adapted for connection to an air line or the like and constituting the sole air inlet for said air chuck, an axial bore constituting an outlet bore extending into said head portion from said front face, a portion of said outlet bore constituting a first recess therein, a valve member received in said first recess, another portion of said outlet bore constituting a second recess coaxial with said first recess, a gasket received in said second recess, and a cap securable in said second recess for holding said valve member and said gasket in assembled relation, a passage in said body providing communication between said inlet bore and said first recess of said outlet bore, said gasket and said cap each having an opening therethrough for the flow of air from said air chuck, said valve member being movable in said first recess from a closed position in which it sealingly engages said gasket for blocking the flow of air from said air chuck and an open position in which it is clear of said gasket thereby permitting air to flow from said passage, past said valve member, and through said openings in said gasket and said cap, these last-said openings constituting the sole air outlet for said air chuck, said cap having external threads thereon and said outlet bore being internally threaded for reception of said cap threads; wherein the improvement comprises said internal threads in said outlet bore being recessed into the outlet bore and a portion of said head portion constituting a lip extending continuously around said outlet bore out beyond said internal threads so that upon said cap being threaded into said outlet bore, the outer face of said cap is substantially flush with the outer edge of said lip whereby said internal threads in said outlet bore and the cap are protected from damage, the plane of said front face intersecting the axis of said inlet bore at an included angle ranging between 20° and 30°, said internal and external threads being buttress threads having a first face generally perpendicular to the longitudinal axis of said outlet bore and a second face inclined to said longitudinal axis, said first face on said internal threads facing inwardly of said outlet bore, said first face of said external threads interengaging said first face of said internal threads whereby said first faces resist internal pressure forces acting on said cap and insure that said cap remains sealed to said body even if said body expands radially due to said internal pressure.