Patent ID: 7790090

Claim:
A method of manufacturing a sheet based on hydraulic binder from a preform intended to be cut, this method comprising the step of providing an apparatus for making an impression in a preform based on hydraulic binder, this apparatus comprising at least: a frame; two first pulleys supported at a first end of the frame and two second pulleys at a second end of the frame; the first pulleys and second pulleys being in parallel planes; the pulleys of the first pulleys and second pulleys facing each other being identical; two transmission belts wrapped respectively around the first pulleys and the second pulleys; and at least one wire fixed removably to the belts and extending across a gap between the two transmission belts so that its longitudinal axis is parallel to the axis of rotation of the pulleys and so that the longitudinal axis of the at least one wire is perpendicular to the direction of travel of the two transmission belts, actuating said apparatus on a preform so that the at least one wire makes an impression on the preform, and actuating a cutting device to cut the preform.