Patent ID: 7155883

Claim:
A packaging machine for wrapping products in respective sheets of heat-seal wrapping material, the machine comprising wrapping means for forming a tubular wrapping from a continuous web of heat-seal material, and for feeding the products successively into the tubular wrapping, each product being located between two free tubular portions of said tubular wrapping; sealing and feed means comprising at least two pairs of sealing devices movable along a sealing path to feed a respective product at a variable travelling speed along the sealing path, and to perform a respective sealing operation on a respective said tubular portion, each sealing device, having a hot sealing surface and being movable along an endless path comprising said sealing path; and, for each sealing device, heating means for electrically heating the respective sealing surface; and being characterized in that each sealing device has control means fitted to the sealing device for moving along said endless path, for determining an actual temperature of the respective sealing surface, and for controlling said heating means as a function of said actual temperature.