Le savoir faire de Power Jacks joue un rôle central à Wimbledon

Power Jacks a joué un rôle essentiel dans la construction du nouveau toit de Wimbledon En janvier 2004, “The All England Lawn and Tennis Club” annonçait le plan de rénovation et la construction d’un toit résistant aux intempéries et entièrement rétractable sur le fameux Centre Court pour le championnat de Wimbledon 2009. Power Jacks était au centre d'un projet de plusieurs millions de livres pour construire le nouveau toit et s'assurer qu’il puisse s’ouvrir en moins de dix minutes.

 The new roof, three years in the making and five years in the planning, is a retractable 5,200 sq metre folding fabric concertina, made from a revolutionary translucent, waterproof material called tenara, which allows natural light in when the roof is closed.

 Power Jacks designed and supplied 42 bespoke electric linear actuators

The design and build of the roof was commissioned by a chosen consortium of companies which included, Sheffield based Street Crane Xpress (SCX), whose role in the build was to focus on the mechanisation and control of the roof, enabling it to open and close depending upon weather conditions.
Power Jacks designed, manufactured and supplied 42 bespoke electric linear actuators to create locking devices, 36 of which operate when the roof opens. We were delighted to have been selected by SCX as a prime technology partner. In providing specialised engineered solutions for this challenging application Power Jacks equipment play an integral part in improving playing conditions on Wimbledon’s Centre Court.

The Power Jacks Group has been supplying products and a continuous after sales support service to SCX for over a decade and have worked on projects with SCX ranging from building maintenance to glass manufacture to mechanical handling.

Daniel Salthouse, Project Manager for SCX, said “Reliability was always the key issue when considering which equipment suppliers to use on the roof. We chose Power Jacks both as a result of the numerous successful projects that we have used their equipment on in the past and because of their ability to meet our demanding specifications”.

The roof, measuring 80 metres long, is divided into two sections with a total of nine bays of structural fabric, four bays in one section and five in the other. Each of the nine bays are clamped on either side by prismatic steel trusses. Altogether there are 10 trusses spanning 77 metres across the court. At the end of each truss there is a set of wheels that glide until the two sections overlap, giving the equivalent coverage of 7,500 open umbrellas!

Much of the roof’s working life will be parked in the open position. When the roof is ready for closing, one section is parked in its folded state at the north end of the court while the other is parked at the south end. Again a combination of actuators and arms form the mechanism for closing the roof at a maximum speed of 214 mm per second. The mechanism moves the trusses apart and, at the same time, unfolds and stretches out the fabric between the trusses over the court until the two sections meet in an overlapping seam above the middle of the court.

The linear actuators used for locking and unlocking the roof segments were specially designed by Power Jacks for the Wimbledon roof using 3D design technology to optimise the design process and integrate with SCX. The actuators design is based on Power Jacks Type-A Rolaram® technology which has been used worldwide in varying industry sectors including automotive, medical, steel and nuclear. Each of the Wimble¬don Rolaram’s® is designed to have a peak load rating of 160kN to withstand forces exerted by nature. They operate at 1500 mm/min over a 400mm stroke with the useable stroke set by limit switches integrated into the actuator. Drive for the actuator is provided by an electric brake motor with an IP66 weatherproof enclosure. Both the motor and the limit switches connect to the electrical control and power systems via plug-in connectors for quick and easy installation. The completed Rolaram® actuator is mounted in the roof using a trunnion to clevis type arrangement that allows the actuator to pivot through an arc as it operates. Just like the players below the actuators are finished in a classic white paint for Wimbledon instead of Power Jacks standard Red.

With the roof folded, the arch shape to the tops of the trusses helps the structure to withstand loading from elements such as snow and wind when the roof is stretched and closed over the court. The shape also assists in providing 16 metres clearance sufficient for even the highest of lobs.

 A key element of the design has been to allow natural light to reach the grass, while an airflow system removes condensation from within the bowl to provide the optimum internal environment for the comfort of spectators and players when the structure is closed.

The roof has been designed to close in under 10 minutes. If the roof is being closed for rain, court covers will protect the grass in the usual way while closure is in progress.