Air Hose: Couplings with Two-Bead Crimped Ferrules

A rubber hose becomes an air hose when couplings are fixed to its ends. John Keenan's fitting (US 4,453,746, 1984, for railway airbrake hoses) has a stem with a stop flange, ridges and a bulbous tip; a ferrule is crimped over it in two beads, the second ending at the bulb's widest point and flaring out so it cannot cut the hose. If a ferrule fails in the field, a band clamp over the ridged recess holds the hose without the crimping machine. The patent gives no sizes or materials. The picture: the patent's Fig. 3.