Patent ID: 9528640
Filing Date: 2016-12-27
CPC Classification: F16L

Claim Text:
1. A tightness-indicating tube fitting comprising: a tube inserted into a body; at least one ferrule disposed around the tube; a nut fastened onto the body to deform the ferrule for providing a seal between the body and the tube; and a check ring having a pressure-receiving section protruding from a side of the check ring facing the nut, the pressure-receiving section having an inner diameter part which is provided with a slope, wherein, when the nut is fastened onto the body by an amount of nut rotation corresponding to a predetermined length, and as the nut moves forward after having made contact with the slope of the pressure-receiving section, a pressing force from the nut acts on the slope of the check ring to detached by breaking the check ring from the body by the pressing force of the nut such that a fastened state of the nut is checked.