Patent ID: 7360347

Claim:
A method of wrapping articles, comprising the steps of: folding a sheet ( 3 ) of wrapping material about a respective article ( 2 ) to form a wrapping ( 9 ) having at least two superimposed portions ( 10 , 11 ); conveying the wrapping ( 9 ) in a first direction (A) along a first path (P 1 ); joining said two superimposed portions ( 10 , 11 ) by transferring heat to the two superimposed portions ( 10 , 11 ) by means of at least one heating head ( 14 ), which is fed in the first direction (A), in phase and in contact with the wrapping ( 9 ), from a contact station ( 22 ) to a withdrawal station ( 23 ), along a second path (P 2 ) extending parallel to at least a portion of the first path (P 1 ); moving the heating head ( 14 ) crosswise to said first path (P 1 ) and said second path (P 2 ), so that the heating head ( 14 ) approaches the wrapping ( 9 ) and is brought into contact with the superimposed portions ( 10 , 11 ) at the contact station ( 22 ); moving the heating head ( 14 ) crosswise to said first path (P 1 ) and said second path (P 2 ), so that the heating head ( 14 ) is withdrawn from the wrapping ( 9 ) at the withdrawal station ( 23 ); and conveying the heating head ( 14 ) from the withdrawal station ( 23 ) to the contact station ( 22 ) along said second path (P 2 ) in a second direction (B) opposite the first direction (A); said heating head ( 14 ) being conveyed from the contact station ( 22 ) to the withdrawal station ( 23 ) at a first speed (V 1 ); the heating head ( 14 ) being conveyed from the withdrawal station ( 23 ) to the contact station ( 22 ) at a second speed (V 2 ) greater than or equal to the first speed (V 1 ); wherein a given number of heating heads ( 14 ) are conveyed together, along said second path (P 2 ); said first speed (V 1 ) and said second speed (V 2 ) being related by the following equation: V 2≧( n - m )× V 1 where V 1 is the first speed (V 1 ), V 2 is the second speed (V 2 ), n is the given number of heating heads ( 14 ), and m is a integer smaller than n; the given number of heating heads ( 14 ) being greater than one.