Patent ID: 6929099

Claim:
A rotary feed-through device for selectively supplying cooling lubricant or air to a rotating machine part, the device including a hollow shaft supported to rotate in a first housing part, a first sealing surface, a sealing bushing coaxial with the hollow shaft and axially movable within a second housing part, and a second sealing surface pressed into continuous contact with the first sealing surface, wherein the second housing part contains a first lateral supply channel attachable to a coolant supply line or a compressed air supply line for supping cooling lubricant or compressed air via at least one radial opening in the sealing bushing, a pressure piston closing the rear end of the sealing bushing for increasing the contact pressure between the sealing surfaces, and a second supply channel charged during the supply of cooling lubricant for supplying cooling lubricant to the pressure piston to increase the contact pressure between the sealing surfaces.