Abstract: A safety valve for pneumatic tools, comprising first and second valve bodies which are movable relative to each other and which carry cooperating seat surfaces. The first valve body is of tubular shape and is displaceable between a closed and an opened position by means of a lever.The second valve body is pressure balanced and biased by a spring to maintain sealing contact with the first valve body as the latter is displaced. A lever operated arresting means is arranged to lock the second valve body against movement and thereby interrupt the sealing contact between the first and second valve bodies as the first valve body is displaced.

Abstract: A pneumatic grinding machine provided with a dust collector which partly surrounds the grinding tool and which is connected to a suction source through a dust conveying conduit. The maneuverability of the machine is improved by utilizing rotatable connections for the dust conveying conduit as well as for the pressure air supply conduit and by arranging said connections rotatable relative to the machine for rotation about a common axis. The rotatability of these conduits is accomplished by swivel means disposed as the outer end of a machine handle. Alternatively, the connections are associated with the dust collector.