Patent ID: 6901725

Claim:
A method of wrapping stacks ( 2 ) of products ( 3 ), the method comprising a feed step, in which a stack ( 2 ) of products ( 3 ) is fed to a radial seat ( 7 ) of a wrapping wheel ( 5 ) rotating in steps about an axis of rotation ( 6 ) to feed said radial seat ( 7 ) in a given travelling direction ( 8 ) and along an endless path (P) extending through a loading station ( 9 ) for loading said stack ( 2 ), and through an unloading station ( 10 ), said stack ( 2 ) being positioned with its longitudinal axis ( 11 ) parallel to said axis of rotation ( 6 ), and being fed to said radial seat ( 7 ) through an output station ( 23 ) of a feed line ( 24 ) supplying heat-seal sheets ( 4 ) of wrapping material, so as to mate with a respective said sheet ( 4 ) of wrapping material at said output station ( 23 ), and engage said radial seat ( 7 ) while folding said sheet ( 4 ) of wrapping material into a U with two opposite lateral flaps ( 25 ) projecting from the relative said stack ( 2 ) and outwards of said radial seat ( 7 ); a first folding step, in which said two lateral flaps ( 25 ) are folded about the relative said stack ( 2 ) to define, about the stack ( 2 ), a tubular wrapping ( 51 ) coaxial with said longitudinal axis ( 11 ) and having a longitudinal rib ( 50 ) defined by superimposed lateral end portions ( 25 a ) of said lateral flaps ( 25 ); a sealing step, in which said lateral end portions ( 25 a ) are sealed to each other; and a second folding step, in which said longitudinal rib ( 50 ) is folded squarely onto an outer surface ( 54 ) of said tubular wrapping ( 51 ); and being characterized in that said two folding steps and said sealing step are performed by folding means ( 26 ) comprising two opposite sealing members ( 45 , 47 ), which perform respective movements to move with respect to each other to and from a closed position contacting each other, and to accompany said radial seat ( 7 ) along a portion (P 1 ) of said path (P) during the folding and sealing steps.