Fluid coupling for hollow rotary member

Claim 1

In combination, a hollow rotary member provided with a shaft having a bore communicating with the interior of said member, and a stationary coupling sleeve coaxially surrounding said shaft with annular clearance, said sleeve beng internally provided with a plurality of elastomeric sealing rings engaging said shaft and bounding at least one compartment within said clearance communicating with said bore through a lateral port of said shaft and further communicating with an external conduit carrying a temperature-controlling fluid circulated through said member by way of said bore, said shaft having a free end constituted by an integral extremity of reduced cross-sectional area and limited axial length with a noncircular outline formed from convex sections merging smoothly and without peripheral discontinuities into one another, the maximum distance of said sections from the shaft axis being at most equal to the radius of said shaft, said extremity being joined to adjacent shaft portions by rounded transition zones enabling said sealing rings to be safely fitted onto the shaft from said free end during assembly.