Patent ID: 11858161
Assignee: FUTURA S.P.A.
Field: Machine tools (Mechanical engineering)
Classification: CPC B | IPC B

Claim 0:
1. A cutting machine for the transversal cutting of paper material logs, comprising:
a structure on which the logs are moved to be transversely cut in order to obtain rolls of shorter length;
a cutting unit arranged at a predetermined point of said structure and comprising a support plate for a blade that is removably connectable to a respective rotary actuator that controls a rotation of the same blade about an axis of the blade at a predetermined speed, said plate being constrained to a further actuator which drags it into rotation with a predetermined angular speed about an axis parallel to the rotation axis of the blade, the blade being arranged along a plane lying perpendicular to said rotation axis at a predetermined position in the cutting unit;
at least one sharpening unit with two grinding wheels, each having an abrasive side, arranged to sharpen the blade on opposite sides with respect to said plane, said grinding wheels being circular wheels having a predetermined radius;
a positioning device for positioning said grinding wheels with respect to the blade arranged on each sharpening unit, by which each grinding wheel is placed in a position of contact with the blade in a blade sharpening position starting from an initial inoperative position;
wherein—said positioning device comprises a primary carriage movable along a primary direction radially with respect to the blade, starting from an initial waiting position, by one or more primary actuators, and two secondary carriages each of which is supported by the primary carriage and can be moved along a secondary direction parallel to the rotation axis of the blade by two secondary actuators;
in a first operation of positioning the grinding wheels, said one or more actuators moving the primary carriage are controlled by a sensor which detects the radius of the blade and stops the primary carriage along the primary direction when the grinding wheels are positioned with the respective axes, with respect to the axis of the blade, at a distance equal to the sum of the radius of the blade and the radius of the grinding wheels minus a predetermined value such that the grinding wheels are moved, along the primary direction, to a position in which the respective abrasive sides can subsequently be brought into contact with the blade;
in a second operation of positioning the grinding wheels, the secondary carriages are controlled so as to bring the abrasive side of the grinding wheels into contact with the blade.