Insulated swivel connection

Claim 1

A fitting for connecting a gas meter having a male screwthreaded hub on a meter top to a gas line to be suspended therefrom, said fitting comprising a pipe nipple having an elongate circumferential groove forming upper and lower shoulders, a connection nut having female screw threads to engage the male screw-threaded hub and having an inwardly extending flange defining a hole through which said nipple extends, the inner surface of the flange sloping downwardly and outwardly away from the nipple, a split stop ring on said nipple resiliently biased to contract and extend into said circumferential groove in said nipple and positioned in engagement with said lower shoulder on the nipple, a first collar of electrically insulating plastic material on said nipple and occupying the space in said groove between said upper shoulder and said stop ring and holding the latter against said lower shoulder, said stop ring having a diameter greater than the diameter of said hole in said connection nut so that if said insulating plastic material should be destroyed or softened, said flange on the nut and said stop ring will engage and prevent the meter from becoming disconnected from said nipple and falling to the floor, said first collar of electrically insulating plastic having a reduced portion forming a neck between and separating said connection nut and said nipple and an outwardly and downwardly extending surface to be engaged by said downwardly and outwardly extending surface of said nut to press said first collar tightly against said grooved portion of the nipple, a second collar of electrically insulating plastic material secured on said nipple and located between and electrically insulating the stop ring and the adjacent end portion of the nipple, and said second collar having an inclined surface making a gastight engagement with the inside edge of the top surface of the hub when the connection nut is screwed tightly on the hub.