Sealing device and longitudinal sealing device comprising such a sealing device

A sealing device for a longitudinal sealing apparatus of a packaging machine, the sealing device having a sealing holder (14) for fixing a sealing jaw (16) of the longitudinal sealing apparatus, the sealing device further including a further sealing holder (18) for fixing a further sealing jaw (20) of the longitudinal sealing apparatus, the sealing holder (14) and the further sealing holder (18) being supported movably relative to each other, and the sealing device further including a mechanical coupling unit (22) which the sealing holder (14) and the further sealing holder (18) are arranged on, wherein the mechanical coupling unit (22) comprises a force transmission element (24) and a further force transmission element (26, 28), the force transmission element (24) being configured, during a sealing, to transmit a provided sealing force to the sealing holder (14) in the form of a pressure force, and the further force transmission element (26, 28) being configured, during a sealing, to transmit the provided sealing force to the further sealing holder (18) in the form of a traction force, wherein the mechanical coupling unit (22) comprises a piston unit (30) with a piston chamber (32) and with a piston (34) supported in the piston chamber (32), wherein the piston (34) is operatively connected with the force transmission element (24) and the piston chamber (32) is operatively connected with the further force transmission element (26, 28).