Visual act has delivered the Ballet Floor for Oslo’s New Opera House along with a winch system for its storage and installation. The 16 x 16 meter ballet floor is partitioned into four sections that, when not in use, are hoisted up into a storage position in the fly tower directly over the stage area. Each section is attached to a double winch that moves the floor from a horizontal position, through a sequence of smooth synchronized transitions, to the final vertical park position.
With the help of a portable remote control radio unit, the winches operate the entire ballet floor. With only two technicians the floor can be changed from Stage to Ballet or vice versa in a short period of time. Each floor can be operated individually and the speed of movement is determined by the operating stage technician, with the help of the remote control joystick.
The floor units are hung by chains from two lifting beams. The cables from the double winch are threaded individually through two pulleys on the beam and fixed to an adjustable anchor point on the ground. Six chains are attached to the centre positions and two are attached to the edge of the section. The synchronization of movements between the two points enable horizontal to vertical transition.
The floor units get their structural strength from a composite made of epoxy and glass fiber on a Diviny cell core. Plywood is mounted with damping rubber on top of the core. The surface finish is a cork mat which gives even more damping. After assembly a dance carpet is laid on top. This gives the opportunity to vary color and structure of the floor without changing the characteristics.
The winches are powered by servo motors and controlled by intelligent servo drives. An industrial computer is mounted in a central cabinet and communicates with the drives by Profibus. The software is a stand-alone version of the Visual ActStage Control System.
When the ballet floor sections are lowered into place on the stage floor, the chains are removed and the lifting beams are returned to the storage position in the fly tower. The edges of the sections are then joined with pneumatic cylinders to provide a smooth and even dance surface.