Gas appliance connector

Claim 1

A flexible gas appliance connector capable of passing the official bending and torsion tests required for certification as a gas appliance connector and comprising a flexible metallic tubing having a coupling member mounted on each end thereof, said tubing including a central spiral grooved corrugated section and end portions on which are mounted the coupling members, the corrugations in said central section being constituted of outwardly projecting ridge portions having rounded crests and steep sides connected by rounded groove portion bottoms, and said end portions each having a diameter corresponding approximately to the diameter of said rounded bottoms, said tubing being characterized in that it has a wall thickness between 0.02 inch and 0.064 inch, and in that said ridge portions of said central section thereof are formed by two substantially similar heliCal corrugations distributing bending and torsion stresses on the tubing over a greater area than is possible with a tubing of the same wall thickness having a single corrugation, the coils of said corrugations being alternately arranged throughout the length of the two pitch corrugation and the steep sides of which are connected at their lower ends by said rounded bottoms, the ridge and groove portions formed by the two helical corrugations being of substantially equal widths so that the wall of said tubing in longitudinal section is sinuously shaped.