Abstract: In an apparatus for dewatering water-containing materials, endless sieve belts (1,2) are passed over rolls (8) bearingly supported within substantially mutually parallel frames (7, 11) one of which is movable in direction to the other and is additionally shiftable in a substantially parallel relation to the other and thus transversely to the direction of said adjusting movement and can be fixed in its position. For facilitating the coordination of said adjusting movement and said shifting movement, a gate-type guide (10) forming abutments is connected with one frame (7) and has its gate (12) shaped like a U having legs (13, 14) of different length, retaining bolts or, respectively, pins (26) of the other frame (11) engaging said gate (12).