Calibrated coupling station for components of capsules and apparatus for preparing such capsules

A calibrated coupling station for components of capsules, the capsules comprising an external body and a bag made of filter material, the coupling station comprising a through seat for stably housing said external body that supports said bag, said through seat being arranged on an articulated sector of an advancement element movable along a frame, the coupling station further comprising at least one grip element with a terminal end aligned with a predefined stop area where said through seat stops, the coupling station further comprising a heat-sealing assembly, the grip element being movable by a first actuation assembly, from a raised configuration in which the terminal end faces and is proximate to and above said through seat, to a lowered configuration in which the terminal end is arranged within said through seat and rests on a bottom of the bag, in turn juxtaposed against an inner face of a base of the external body, wherein the grip element is configured to reach an intermediate configuration, arranged within said through seat, between the lowered and raised configurations, at a distance from the base of the external body higher than the lowered configuration, for calibrated positioning in which said terminal end, stably coupled to the bottom of said bag, is arranged at a predefined distance from the inner face of the base of the external body, said terminal end of the grip element being configured to retain said bag when said grip element moves from the lowered configuration up to the intermediate configuration, and wherein said heat-sealing assembly is translatable coaxially with the grip element within said through seat when the grip element is in said intermediate configuration so as to heat seal an external lateral surface of the bag against an internal lateral wall of the external body when the bag is retained by the terminal end of the grip element.