Outside locking tracheal tube

Claim 1

A tracheotomy tube comprising a. an outer, elongated cannula, and b. an inner, elongated cannula, c. each of said cannulas having (1) a proximal end portion, (2) a distal end portion, and (3) a bore extending longitudinally therethrough, d. said inner cannula being removably mounted in said bore of said outer cannula with a snug, freely slidable fit, e. said outer cannula comprising (1) a tubular body portion (a) forming said distal end of said outer cannula, and (b) extending to said proximal end of said outer cannula terminating in a free end face, (2) an enlarged portion on said proximal end thereof defining an end face, and (3) a collar rotatably mounted on said enlarged portion for rotation on said enlarged portion around the longitudinal axis of said bore in said outer cannula, f. said collar having a front wall slidably disposed over said end face of said enlarged portion and defining the free end face of said proximal end of said outer cannula, g. said enlarged portion having an elongated recess in said end face thereof with segments of the perimeter being substantially non-parallel to the perimeter of said bore in said outer cannula, h. said recess projecting radially outwardly from said bore in said outer cannula, i. said front wall having an opening therethrough, j. said opening being complimentary in size and shape to said recess in said end face of said enlarged portion of said outer cannula and being aligned therewith, k. said collar being rotatable on said enlarged portion between (1) one position wherein said opening is disposed in parallel alignment with said recess, and (2) another position wherein said opening is disposed out of said parallel alignment with said recess, l. said inner cannula proximal end having an elongated flange projecting radially outwardly therefrom and being sized and shaped to fit in said recess, m. said inner cannula being movable axially through said opening into and out of position in said outer cannula wherein said flange is disposed in said recess when said collar is disposed in said one position, and n. said collar being rotatable from said one position to said other position, when said flange is so disposed in said recess, to thereby dispose said front wall in overlying relation to said flange in position to prevent movement of said inner cannula out of said outer cannula.