Patent ID: 8707662

Claim:
A packaging machine for producing sealed packages of a food product from a web of packaging material; said web comprising a first and a second longitudinal edge opposite each other; said machine comprising: forming means defining a compulsory passage for said web, and for keeping said first and second longitudinal edge superimposed to form a tube of packaging material, and being located outside said tube; said first and second longitudinal edge defining, when superimposed, a surface of uneven thickness facing inwards of said tube; and at least one pressure roller which is located inside said tube and presses said surface of uneven thickness against said forming means to form a longitudinal seal of the tube; wherein said pressure roller comprises: a body made of elastically deformable material for pressing said sheet material; and a core made of more rigid material than said body housed inside said body and angularly integral therewith; said core comprising an outwardly facing surface cooperating with said body, and an inwardly facing surface radially inner with respect to said outwardly facing surface and surrounding a hollow portion of the core; said core comprising at least a first portion and a second portion which each contact the body; the radial distance between said inwardly facing surface and said outwardly facing surface at said first portion being greater than at said second portion; said core comprising a first axial end face and a second axial end face positioned at opposite axial ends of the core, the first portion extending from the first axial end face toward the second portion, the second portion extending from the second axial end face toward the first portion.