Pivotable and sealable cap assembly for opening in a large container

In combination, a large container (38) having a top aperture and a circumferential skirt (12) extending upwardly from said container around said aperture and a cap unit (10) for covering said top aperture said cap unit (10) comprising a cap (20) movable between a first position and a second position, said cap (20) in said first position covering and sealing the aperture and said cap (20) in said second position, at least partly uncovering the aperture, said cap (20) being journalled pivotably around a pivot axis (26) which is located laterally outwardly of the area of said cap (20) and which extends perpendicularly to a plane defined by said cap (20) so that said cap can swing in a plane parallel with the plane defined by the aperture between the first position and the second position, and said cap (20) and the skirt (12) having respective claw-forming catching means (14, 16, 18) constructed and arranged to maintain said cap (20) in its first position axially in relation to said skirt (12) by engaging in said skirt (12) and over said cap (20) and at the same time allow said cap (20) to swing from said first position to said second position around said pivot axis (26) defined by a bolt (26) located radially outwardly from said cap (20), said cap unit (10) having driving means (34) for swinging said cap (20) between said first and said second positions and vice versa, means (32) for supporting said cap (20) during swinging movement between the first and second positions comprising (a) a plate (24) fixed to said cap, (b) an arcuate track (32) firmly connected to one of the top wall of the container or the skirt (12), a center of an arc of the track being on said pivot axis, and (c) bearing means between said plate and said track (32) for supporting said plate on said track (32), and said cap unit (10) having an inflatable sealing ring (22) which is mounted in one of an underside of said cap (20) and an upper facing side or surface of the skirt (12) for sealing against the upper side or surface of the skirt (12) when said cap (20) is in its first position or alternatively mounted on the upper side or surface of the skirt (12) for sealing against an opposite side or surface of said cap (20) when it is in its first position.