Pipe coupling

The present invention relates to a pipe coupling comprising a cylindrical coupling member fabricated of shape memory alloy and a foil as a metallic member of low melting point attached to an internal surface of the cylindrical coupling member, whereby the melting point of the foil is lower than that of the materials of a pipe to be joined to the pipe coupling and of the coupling member. According to another aspect of the invention a pipe coupling comprises a cylindrical coupling member (12) fabricated of shape memory alloy, at least two pieces of ring protrusions (13) formed on an internal surface of the cylindrical coupling member (12), and a metallic member (22) of low melting point which is attached to an internal surface of the cylindrical coupling member (12) between the ring protrusions (13), whereby the melting point of the metallic member (22) of low boiling point is lower than that of the materials of a pipe to be joined and of the coupling member (12). In accordance with a further aspect to the invention, a pipe coupling comprises a cylindrical coupling member fabricated of shape memory alloy, a ring stopper formed at a central portion of the cylindrical coupling member in the axial direction thereof, and a metallic member of low melting point attached to both sides of the ring stopper, whereby the melting point of the metallic member of low melting point is lower than that of the materials of a pipe to be joined and of the coupling member.