Patent ID: 8746004

Claim:
A machine comprising: a housing; a cylindrical-shaped processing tub that extends within the housing, from an upper wall thereof, remaining coaxial to a reference axis; means for cooling the processing tub so as to bring and hold the contents thereof at a temperature lower than 0° C.; and a mixing member rotatably mounted within the processing tub about a rotation axis substantially coinciding with the reference axis; the mixing member being fixed onto the upper end of a drive shaft that projects into the processing tub through the bottom of the processing tub, and being structured to mix ingredients within the processing tub and to scrape at least an inner surface of the processing tub to prevent the ingredients from adhering to a side wall of the tub; and an annular containing collar which is dimensioned so as to be fitted in a-releasable manner in the processing tub above the mixing member, and structured so as to retain within the processing tub the ingredients that the mixing member tends to push upwards, along the side wall of the tub, wherein the containing collar comprises a cylindrical sleeve which is dimensioned so as to be forced into the inlet of the processing tub, and is internally provided with a protruding annular flange that protrudes from the inner surface of the sleeve towards the centre of the sleeve.