Patent ID: 8333050

Claim:
A machine for making filter bags ( 103 ) for infusion products and wrapping them in outer envelopes ( 101 ), the machine ( 102 ) comprising: a plurality (L) of stations for making filter bags ( 103 ), each comprising at least one lobe for containing a charge of product, said plurality (L) of stations extending along an operating direction (D); movement devices ( 106 ) for moving the filter bag ( 103 ), along said operating direction (D), for positioning the filter bag ( 103 ) in a wrapping station ( 107 ) for wrapping a flat sheet (S) of overwrapping material around the filter bag ( 103 ) for forming a “U”-shaped wrapper around the filter bag ( 103 ) with at least two opposite wings between which the filter bag ( 103 ) is interposed; and a closing station ( 109 ) for closing two longitudinal end edges (S 1 , S 2 ) and a transversal end edge (S 3 ) of said “U”-wrapped sheet (S) to form a single outer envelope ( 101 ), said machine ( 102 ) being characterised in that said closing station ( 109 ) comprises at least one joining carrousel ( 110 ) equipped with a plurality of sealing elements ( 112 ) for receiving respective single filter bags ( 103 ) with said folded overwrapping sheet (S); each sealing element ( 112 ) being movable in rotation with said joining carrousel ( 110 ) and being designed to allow simultaneous closing of said two longitudinal end edges (S 1 , S 2 ) and of said transversal end edge (S 3 ) of said sheet (S); each sealing element ( 112 ) being divided into two half-parts ( 111 a , 111 b ) projecting from said joining carrousel ( 110 ); the entirety of at least one of said half-parts ( 111 a , 111 b ) being hingedly attached to said joining carrousel ( 110 ) so that each sealing element can define an open pickup or release condition for the outer envelope ( 101 ) in which the half-parts ( 111 a , 111 b ) are separated, and a closed joining condition in which the half-parts ( 111 a , 111 b ) are closed together; wherein the components that receive and hold the outer envelope ( 101 ) within the sealing element ( 112 ) consist of the two half-parts ( 111 a , 111 b ); and wherein the two half-parts ( 111 a , 111 b ), acting together, are each necessary to hold the outer envelope ( 101 ) during the closing operation.