GB839531A - Improvements relating to end fittings for corrugated metal tubing - Google Patents

Abstract

839,531. Pipe couplings. K. A. C. Ltd. Feb. 16, 1959 [April 21, 1958], No. 12646/58. Addition to 809,803. Class 99(1). An end fitting for corrugated metal tubing 1 having an uncorrugated end portion 2 and an external tubular reinforcement 6, e.g. a metallic braid, comprises an annular sleeve 3 having the internal surface 4 thereof configurated to conform with the external corrugations of the tubing and an annular surface 8 thereon located to engage the exterior of the portion 2 and inclined to the axis of the sleeve, a tubular ferrule 9 having a spigot 10 fitting within the bore of the tubing and an annular surface 12 complementary to the surface 8 and located to engage within the bore of the portion 2 to trap that portion between the surfaces 8, 12, and a retaining ring 15 surrounding the reinforcement to trap the latter between the ring and sleeve, there being means for coupling the sleeve and the ferrule against axial relative displacement to release the portion 2, and means for securing the ring 15 to the sleeve in reinforcement trapping relationship thereto. As shown, the ferrule is formed with a shoulder 13 constituting a stop for a ring nut 14 screwed into the skirt 7 of the sleeve 3 to displace the latter and ferrule axially of one another to draw the surfaces 8, 12 together for gripping the tubing portion 2, and the sleeve has an external, tapered, knurled portion 5 complementary to the internal tapered surface of the ring 15, the latter being drawn into a reinforcement-gripping position by a collar 16 screwed on to the skirt 7. When the tubing is provided with helical corrugations the sleeve is screwed on to the tubing; otherwise, the sleeve is in two or more parts fitted around the tubing. The collar 16, sleeve 3 and nut 14 may be drilled and tapped to receive a locking screw. In a modification, the reinforcement-retaining ring is drawn over and secured to the sleeve by a second ring nut. In further modifications, (a) the sleeve and ferrule are coupled together by complementary screw-threads on these parts, (b) the reinforcement-retaining ring and sleeve are secured together by complementary screw-threads thereon in which case, to prevent the transmission of torque to the reinforcement, the ring may be in two parts, one part engaging the reinforcement and the other part being adapted to rotate relatively to the first part and the sleeve, and (c) the ring is swaged on to the sleeve.