Abstract: The funnel member of a single-screw extruder comprises a housing and a feed screw which passes at least partially axially therethrough and is sealed from the drive shaft by a return feed screwthread covered by a bushing which is fixed with respect to the housing. The feed screw is enveloped by a grooved sleeve having take-in grooves which are parallel to the axis and become shallower in the feeding direction. For charging the material, the funnel member is provided with an eccentric filling aperture tangential to the feed screw. To reduce torque and pressure fluctuations caused in the charged thermoplastic masses by the threads of the screw running past the single aperture, the grooved sleeve (9) is provided with take-in grooves (10, 11) over its entire circumference only in the zone upstream of the filling aperture (4) and, in the region of the filling aperture (4), is provided with take-in grooves (10) only in the part substantially radially opposite to the filling aperture (FIG. 3).