Method and machine for cutting logs of wound web material

1. An arrangement comprising:

a cutting machine for cutting logs of web material comprising:

a feeding path for logs to be cut;

a cutting head arranged along the feeding path, said cutting head comprising a coupling for a disc-shaped cutting blade, and said cutting head being configured to impart the disc-shaped cutting blade a rotary motion around an axis thereof and a cyclic movement to cut the logs into rolls, and to allow the logs to move forward along the feeding path;

at least one store unit for disc-shaped cutting blades adapted to store a plurality of the disc-shaped cutting blades;

at least one handling member, which is movable with respect to the cutting head, to remove the disc-shaped cutting blade from the cutting head when the disc-shaped cutting blade is a worn disc-shaped cutting blade to be replaced, and to replace the worn disc-shaped cutting blade with a new disc-shaped cutting blade taken from the store unit;

wherein the store unit comprises a blade-holder adapted to house the plurality of disc-shaped cutting blades with respective disc-shaped cutting blade axes being aligned according to an alignment direction substantially parallel to the feeding path; wherein the blade-holder is adapted to move the disc-shaped cutting blades substantially parallel to the blade axes to selectively bring each disc-shaped cutting blade in a pick-up or load position with respect to the cutting head; and wherein the at least one handling member is adapted to position a worn disc-shaped cutting blade removed from the cutting head into an empty seat of the store unit, and is adapted to pick up a new disc-shaped cutting blade from the store unit and attach the new disc-shaped cutting blade to the cutting head.

2. The arrangement of claim 1 , wherein the store unit is arranged above or on a side of a cutting station comprising the cutting head.

3. The arrangement of claim 1 , wherein said blade-holder comprises a series of seats configured to retain the plurality of disc-shaped cutting blades.

4. The arrangement of claim 3 , wherein said blade-holder is configured to be movable to bring an individual seat of said seats into the pick-up or load position to allow removal of a new disc-shaped cutting blade from the blade-holder or insert a worn disc-shaped cutting blade in the blade-holder.

5. The arrangement of claim 4 , wherein the blade-holder is slidingly connected to a stationary guide.

6. The arrangement of claim 1 , wherein said plurality of disc-shaped cutting blades in said store unit are arranged substantially coaxial to one another.

7. A method for cutting logs of wound web material, comprising steps of:

moving logs of web material sequentially along a feeding path in a direction parallel to axes of the logs;

cutting the logs by a disc-shaped cutting blade mounted on a cutting head and severing the logs into rolls of an axial length smaller than that of the logs, the cutting head moving the disc-shaped cutting blade with a cyclical motion to cut the logs and allow a forward movement of the logs along the feeding path;

periodically grinding the disc-shaped cutting blade;

when the disc-shaped cutting blade is so worn that the cutting blade is a worn disc-shaped cutting blade to be replaced:

temporarily stopping the forward movement of the logs;

removing the worn disc-shaped cutting blade from the cutting head, taking a new disc-shaped cutting blade from a store unit, transferring the new disc-shaped cutting blade to the cutting head and mounting the new disc-shaped cutting blade on the cutting head; and

once the new disc-shaped cutting blade has been mounted on the cutting head, re-starting the forward movement of the logs along the feeding path;

wherein the store unit comprises a blade-holder arranged and configured to keep a plurality of disc-shaped cutting blades with respective cutting blade axes aligned according to an alignment direction substantially parallel to the feeding path;

wherein the blade-holder is adapted to move the plurality of disc-shaped cutting blades in a direction substantially parallel to the blade axes and to the alignment direction; and

wherein at least one handling member is adapted to position the worn disc-shaped cutting blade removed from the cutting head into the store unit, and is adapted to pick up the new disc-shaped cutting blade from the store unit and attach the new disc-shaped cutting blade to the cutting head.

8. The method of claim 7 , further comprising positioning the store unit above or on a side of the cutting head.

9. The method of claim 7 , wherein the blade-holder includes a series of seats configured to retain the plurality of disc-shaped cutting blades.

10. The method of claim 9 , further comprising configuring said blade-holder to be movable to said pick-up or loading position.

11. The method of claim 10 , further comprising slidingly connecting the blade-holder to a stationary guide.

12. The method of claim 7 , wherein said plurality of disc-shaped cutting blades in said store unit are arranged substantially coaxial to one another.