Calender for the treatment of web-like materials, including a fixed structure supporting two heated rollers reciprocally arranged so as to form a nip traversable by web-like materials, where each roller has pins mounted on bearings. The structure includes two lower levers and two upper levers adapted for exerting on the bearings forces oriented according to not coinciding directions, each lever being connected with an actuator that controls its rotation around a horizontal axis to put it in a first engagement position of the respective bearing and in a second release position, such that in the second position of the levers the extraction of the rollers from the calender is allowed.

An apparatus for producing a web of fibrous material includes a roll having incisions with a depth of 0.01-2.00 mm, a width of 0.01-2.00 mm, and a pitch 0.01-10.00 mm, and rotated at a peripheral velocity v.sub.1 equal to the velocity of an upstream apparatus unit; a belt stretched between transmission rollers that advances at a velocity v.sub.2 less than v.sub.1, wherein v.sub.1/v.sub.2 lies between 1.05 and 1.40; a presser roller rotating at a peripheral velocity v.sub.2, associated with a presser system acting to press the belt against the metal roll with a pressure of 1-200 kg per centimeter; and a system that feeds a sheet of pliable fibrous material between the belt and the roll, the belt having a longitudinal elongation of no more than 5%, dimensional stability along its entire length, a thickness of 1-10 cm, and a hardness 24-70 Shore.

An apparatus for producing a web of fibrous material includes a roll having incisions with a depth of 0.01-2.00 mm, a width of 0.01-2.00 mm, and a pitch 0.01-10.00 mm, and rotated at a peripheral velocity v.sub.1 equal to the velocity of an upstream apparatus unit; a belt stretched between transmission rollers that advances at a velocity v.sub.2 less than v.sub.1, wherein v.sub.1/v.sub.2 lies between 1.05 and 1.40; a presser roller rotating at a peripheral velocity v.sub.2, associated with a presser system acting to press the belt against the metal roll with a pressure of 1-200 kg per centimeter; and a system that feeds a sheet of pliable fibrous material between the belt and the roll, the belt having a longitudinal elongation of no more than 5%, dimensional stability along its entire length, a thickness of 1-10 cm, and a hardness 24-70 Shore A.

An apparatus for producing a web of fibrous material includes a roll having incisions with a depth of 0.01-2.00 mm, a width of 0.01-2.00 mm, and a pitch 0.01-10.00 mm, and rotated at a peripheral velocity v.sub.1 equal to the velocity of an upstream apparatus unit; a belt stretched between transmission rollers that advances at a velocity v.sub.2 less than v.sub.1, wherein v.sub.1/v.sub.2 lies between 1.05 and 1.40; a presser roller rotating at a peripheral velocity v.sub.2, associated with a presser system acting to press the belt against the metal roll with a pressure of 1-200 kg per centimeter; and a system that feeds a sheet of pliable fibrous material between the belt and the roll, the belt having a longitudinal elongation of no more than 5%, dimensional stability along its entire length, a thickness of 1-10 cm, and a hardness 24-70 Shore A.