US Patent 7735667 Sleeve nut of plastic material

A plastic screw cap includes two cap halves, which are produced as plastic injection-molded parts and have an internally threaded segment and an inwardly directed ring shoulder segment. The two halves of the screw cap can be pushed together, for example, on the inlet connection of the valve body of a flap valve by tongue-and-groove joints. One cap half has two hook-like ends, each of which is provided with an inwardly sloped clamping sidepiece and a groove for receiving the tongues formed on the two ends of the other half of the screw cap.