Hydraulics from Bosch Rexroth will drive The Great Wheel, in which 40 passengers per capsule will get a state-of-the-art audiovisual description of Beijing and the surrounding area, including the Gate of Heavenly Peace in the Forbidden City. (Great Wheel Corp. illustration.)

The 678 ft (208 m) wheel will include 48 capsules for 40 passengers each, who can enter and exit while the wheel is turning. A powerful, nearly maintenance-free hydraulic power unit will drive 32 special tires that push the wheel at a constant rotation of three times per hour. Bosch Rexroth is providing project engineering, shipment and installation of the hydraulic drive and control systems, and the automation for the passenger boarding stations.

Automation equipment will move boarding stations on each side, synchronized with the motion of the Great Wheel to avoid unnecessary stops and starts and the potential loss of inertial energy. Passengers will board via special cars on a separate track. These cars will then travel alongside to match the speed of the wheel at the bottom of its rotation so passengers can transfer in and out at a rate of nearly 5,800 passengers per hour. Design emphasis on reliability and safety, with a fail-safe backup system ensuring reliable operation even if a fault develops in the main circuit.

Rexroth’s line of standard hydraulic power units and modules are based on modular design concepts for consistency, low cost, and quick delivery, the company says. The units range from 2.5 to 100 gal. units, providing power from 0.5 to 50 hp and 0.4 to 31 gpm (fixed or variable displacement), with operating pressure to 3,000 psi. Custom designs can meet space restrictions or application-specific needs.

Other giant wheels, according Wikipedia, include the British Airways London Eye, also known as the Millennium Wheel. That opened in 1999 and is 135 m (443 ft) high. Rexroth also powers that wheel, the largest in Europe. Compared against other giant wheels planned or under construction (including Las Vegas and Berlin), the Beijing wheel is the largest. The original Ferris wheel at the 1893 World’s Columbian Exposition in Chicago was 75 m high.

www.greatwheel.com; www.boschrexroth.com