Unit for over-wrapping filter bags for infusion products

A unit for over-wrapping filter bags for infusion products obtained from a machine for forming filter bags for infusion products starting from pieces of filter material each containing at least one dose of infusion product and including a formed filter bag, a thread and a tag;

• the unit for over-wrapping comprising at least:
• a carousel rotating about a first axis of rotation and including at least one first and one second gripping devices including grippers movable in rotation about the first axis of rotation along a closed circular trajectory;
• a forming station for forming single sheets of over-wrapping material arranged adjacent to the closed circular trajectory of the first and second gripping devices;
• a feeding device, positioned in the forming station, for feeding the single sheets of over-wrapping material prepared in a U-shape, in phase synchronization with the rotation of the carousel, only on the first gripping device;
• a first drum configured for transport of the formed filter bag, rotating about a second axis of rotation parallel to the first axis of rotation, and having a gripping device configured to receive the formed filter bags from a preceding station or carousel and to release, in phase synchronization with a corresponding rotation with the carousel, the filter bags only on the first gripping device including the U-shaped sheet of over-wrapping material;
• the first gripping devices being configured to enable positioning and retaining of the formed filter bag inside the same U-shaped sheet of over-wrapping material;
• a closing station of the sheet of over-wrapping material on the formed filter bag arranged adjacent to the closed circular trajectory of the first and second devices;
• the closing station including a sealing gripper connected to movement elements able to move the sealing gripper, in phase synchronization with the rotation of the carousel, from a first position close to the carousel, for collecting the formed filter bag with the sheet of over-wrapping material from the first gripping devices, to a second position away from the carousel, for closing the sheet of over-wrapping material and, lastly, to a third position newly and again close to the carousel, for release of the formed filter bag closed by the sheet of over-wrapping material only to the second gripping device.