Abstract: A fiber feed channel of an open-end spinning apparatus is divided by a parting face into a stationary part and a movable part, including a pivoted cover. The parting face includes an elastic O-ring, the surface of which is disposed at a predetermined minimum angle .alpha. relative the direction of movement of the pivoted cover. Such orientation ensures a relatively perpendicular component of contact between the O-ring and the pivotal cover, thereby reducing sliding friction between the two which prolongs the life of the O-ring while providing a good seal. Two interacting elements, one arranged on the cover and the other arranged on the spinning element housing, define a stop for positioning the cover relative to the spinning element.