no detailed discussion with a continuously variable drive so as to permit continuous variation in the number of rotations of the shafts 3 and thereby the shafts 2a the drive may either be a conventional well known variable motor or as illustrated a hydrostatic drive 4 which is also known per se to those skilled in the art and therefore not discussed in detail essential in connection with the drive 4 is only that it be continuously variable to permit continuous variation in the rotations of the shafts 3 and accordingly the shafts 2a a weight in form of a plate 5 is so configurated as to be receivable through the open top of the mold which latter is identified with a legend in fig1 as is the material to be compacted contained in the interior of the mold and rests on the granular mass located in the mold it serves the dual purpose of weighing the material and of assuring that the upper surface of the finally produced coherent body will be smooth in accordance with the smooth underside of the plate 5 it is to be noted that the plate 5 is freely received in the open top of the mold located above the mold is a traverse 7 which is connected via the tie rods 8 with the vibratory platform 1 and supports a cylinder and piston arrangement 6 the cylinder and piston arrangement 6 is associated with the plate 5 and able to impart stresses thereto in a sense pressing it deeper into the mold thereby serving to compress the granular mass contained therein it operates preferably either with compressed air or on an oil hydraulic basis details concerning these features need not be discussed.