Infusion cannula assemblies

Claim 1

An infusion cannula assembly, comprising a connection piece made of thermoplastic material, a mounting sleeve integrally formed at one end of said connection piece, a flexible cylindrical cannula tube made of plastic material with a low friction coefficient, first wall means at one end of said mounting sleeve forming in said mounting sleeve a cylindrical mouth channel of a diameter corresponding to the outer diameter of said cannula tube, second wall means of said mounting sleeve forming a cylindrical mounting chamber in said mounting sleeve coaxial with and merging into the mouth channel formed by said first wall means, the mounting chamber formed by said second wall means having a diameter greater than that of the mouth channel, third wall means of said mounting sleeve forming a cylindrical connection chamber coaxial with and merging into the mounting chamber formed by said second wall means and having a diameter greater than that of the mounting chamber, an annular shoulder connecting said second and third wall means between the mounting chamber and the connection chamber, a snap collar protruding inwardly from said third wall means at an axial distance from said shoulder, one end of said cannula tube extending through the mouth channel into the mounting chamber, a tubular metal insert mounted in said end of said cannula tube and keeping said cannula tube end expanded into engagement with said second wall means throughout the axial length of said second wall means, and an outwardly directed circumferential flange integrally formed at one end of said insert and abutting said cannula tube end, said flange being disposed in the connection chamber between said shoulder and said snap collar and being movable past said snap collar with snapping action, said snap collar cooperating with said flange to restrain the metal insert from sliding out of the cannula tube.