Regulatable triggers for pneumatic devices

Claim 1

A pneumatic tool control device comprising means for supplying air under pressure from an external source to a work chamber within a housing, and a regulatable trigger valve mounted in a bore within said housing, said housing including a first passageway establishing pneumatic communication between the bore and the work chamber and a second passageway establishing pneumatic communication between the bore and the external source, and said trigger valve including a cylindrical shell removably secured to the housing and being provided with a diametrally reduced annular neck portion at the intersection of the first passageway and the bore, a first radially extending port located in the annular neck portion of the shell, a coaxial cylindrical sleeve rotatably mounted in the shell and being provided with a second radially extending port, and a plunger slidably mounted in the sleeve and spring biased against the housing to a normally closed position between the first passageway and second passageway, said first and second ports being substantially the same size and being located at substantially the same axial position on the common axis of the shell and the sleeve, whereby as the sleeve is rotated within the shell the degrees of overlap between the first and second ports may be selectively varied and the size of the resultant aperture between the external source and the work chamber may be selectively varied.