Pressure gauge

Claim 1

A pressure gauge for measuring and indicating pressure of a fluid comprising, an elongate tubular body having open, opposite ends, connecting means on one end of said body for connecting said pressure gauge to a source of pressure to be measured, said body having a reduced diameter at its other end extending over a major portion of the length of said body and defining a shoulder on said body between said one end and said reduced diameter portion, pressure indicating indicia on said reduced diameter portion of said body, an elongate, longitudinally extending pressure chamber within said body and extending over a major portion of the length of said body, an inlet port opening through said one end of said body into one end of said pressure chamber and having a substantially smaller cross sectional area and length than said pressure chamber, the other end of said body having an annular shoulder on the inner surface thereof with an annular, peripheral, upstanding flange therearound, an annular, ring shaped head member having a central opening therethrough and an annular peripheral flange resting on said shoulder, said upstanding flange on the end of said body swedged over said flange and securing said head member in place in said other end of said body, an elongate, longitudinally extending piston rod slidably extending through said opening in said head member and into said pressure chamber and having a length such that when at rest, one end of the piston rod is positioned adjacent said one end of said pressure chamber and the other end of said piston rod extends through said opening in said head member and projects beyond said other end of said body, a piston head on said one end of said piston rod for reciprocation in said pressure chamber and responsive to pressure changes within said pressure chamber to cause reciprocation of said piston head and said piston rod, a cylindrical transparent indicating sleeve having a closed end and an open end and axially adjustably secured at its closed end to said other end of said piston rod externally of said body with said indicating sleeve disposed in close surrounding relationship over said reduced diameter portion of said body, an indicating mark around said transparent indicating sleeve adjacent the open end thereof for cooperation with said indicia on said body to indicate the presence of high or low pressure in said pressure chamber, stop means on said piston rod within said pressure chamber arranged to engage said head member in said other end of said body to limit outward movement of said piston rod and said transparent indicating sleeve relative to said body, and compression spring means about the piston rod and engaged between said piston head and said head member in said other end of said body for urging said piston head, said piston rod and said transparent indicating sleeve toward said one end of said body against the force of fluid pressure within said pressure chamber.