Flow gun

Claim 1

A GUN FOR DISPENSING FLUID MATERIALS UNDER PRESSURE COMPRISING A BODY DEFINING A MATERIAL CHAMBER HAVING AN INLET AND AN OUTLET AND A MATERIAL SUPPLY PASSAGE COMMUNICATIVELY COUPLED WITH SAID INLET, VALVE MEANS OPERABLE IN THE CHAMBER TO OPEN AND CLOSE SAID OUTLET AND INCLUDING A RECIPROCABLE ROD PROJECTING AXIALLY INTO THE CHAMBER HAVING A U-SHAPED YOKE AT THE REAR END THEREOF AND A HOLLOW BALANCED CLOSURE PISTON MOUNTED ON THE ROD AND ADAPTED TO SEALINGLY SEAT WITHIN SAID OUTLET, A GUIDE MEMBER FIXEDLY MOUNTED ENCIRCLING SAID VALVE ROD AND PROJECTING GUIDABLY INTO SAID PISTON, SPRING MEANS OPERABLY COUPLED TO SAID VALVE MEANS YIELDABLY URGING THE LATTER TO A NORMALLY CLOSED POSITION, AND TRIGGER MEANS PIVOTALLY MOUNTED ON SAID GUN BODY HAVING A LATERALLY PROJECTING PIN FIXED THERETO EMBRACED BY SAID VALVE ROD YOKE WHEREBY PIVOTAL MOVEMENT OF SAID TRIGGER IMPARTING ARCUATE MOVEMENT TO SAD PIN PRODUCES A SUBSTANTIALLY AXIAL FORCE ON SAID VALVE ROD TO SHIFT THE VALVE TO ITS OPEN POSITION, SAID PISTON EXHIBITING A RELATIVELY SMALL EFFECTIVE AREA EXPOSED TO PRESSURE OF SAID MATERIAL IN THE CHAMBER TO ENABLE ACTUATING OF SAID VALVE MEANS OPENING SAID OUTLET WITH A MINIMUM FORCE EXERTED ON SAID TRIGGER.