A convertible stadium includes an exhibition area, a seating area and a plurality of roof support locations for supporting a movable or retractable roof assembly. The roof assembly includes a first major truss that spans a distance between a first and a second of the roof support locations and a second major truss that spans a distance between a third and a fourth of the roof support locations. Both of the first and second major trusses are preferably structurally configured as a tied arch, each of which has a generally convex upper portion and a lower portion that is adapted to assume gravity induced stresses within the trusses as tension. In order to keep the center of mass of the major trusses generally positioned within a plane including the roof support locations, which optimizes lateral stability of the major trusses, the major trusses are most preferably given a lenticular shape, meaning that the lower portion of the trusses is convex and in fact preferably generally symmetrical to the upper portion. First and second convex guide tracks are respectively mounted to the upper portions of the first and second major trusses, and a movable roof member is mounted for movement along the guide tracks. Advantageously, the guide wheels and the drive wheels on the movable roof member engage the upwardly facing and downwardly facing surfaces on the guide tracks, and are biased together so as to provide sufficient traction to be able to move the movable roof member along the guide tracks even when such movement has an upward component due to the convex shape of the guide tracks.
This application claims priority under 35 USC .sctn.119(e) based on U.S. Provisional Application Ser. No. 60/263,645, filed Jan. 23, 2001, the entire disclosure of which is hereby incorporated by reference as if set forth fully herein.
The invention pertains to a covering structure for covering swimming pools, including several pairs of parallel arches that serve to support flexible panels, the arches being made from a curved profile having lateral walls delimiting a series of parallel guide grooves arranged one above another and perpendicularly to a plane of the arch and receiving the panels, and a protective and elevating border disposed on a lateral edge of at least one of the panels contacting at least one of the internal faces of the guide groove, the height of said border being sufficient to prevent the latter from contacting the profile.
A movable roof member includes a transport mechanism that is constructed and arranged to permit the roof member to move in a predetermined path with respect to the underlying structure of the supporting edifice. The transport mechanism includes structure for supporting both ends of the roof member, which bridges an otherwise open area of the edifice. In order to permit some flexure and movement of the roof member with respect to the underlying edifice, as will inevitably occur as a result of natural forces such as winds, a lateral release system is provided for maintaining the transport mechanism in a predetermined orientation while simultaneously permitting a limited amount of movement of the roof member in a direction that is nonparallel to the predetermined path of movement. The lateral release system has been found to be most effective when it is provided at but one end of the roof member. The lateral release system preferably includes a linear slide bearing that in the preferred embodiment has a longitudinal axis that is oriented so as to be substantially perpendicular to the predetermined path of travel of the roof member.
A bang-bang servo system controls motors which provide drive for trucks on each end of a fabric support beam structure. A plurality of such truck/beam/fabric units comprise a retractable roof Separation of inner and outer truck guiding tracks/support platforms may be wide and somewhat variable. The radius of curvature of the inner and outer tracks may vary widely over the beam excursion path between open and closed roof conditions. Individual beam motion sequencing and stop position are commanded through a central control unit. These features allow great flexibility and adaptability in application of this invention.
