Special bearing lifts positioning

A special bearing has been developed to improve the positioning accuracy of high speed lifts in tall buildings. It has been developed to address the problem of lift cabins in high speed lifts, especially those in high rise buildings not always stopping at exactly the right position. The problem is often found to be associated with inaccuracies and slippage of cabin sensor wheels running on the rails in the shafts. Determining position from the lift hoist on its own is not sufficient in a high rise building since lifting cables can stretch and undergo thermal expansion and contraction. This has led to the Fribourg, Switzerland headquartered Jesa company developing a special product - a wheel with a double row ball bearing in a hard plastic wheel disk with an over-moulded thermoplastic tyre that is relatively soft. The hard plastic bearing hub contributes to reduced vibration and noise levels, while maintaining the rigidity and accuracy of the circumference. The softer tyre, on the other hand, provides improved sensor track adhesion and minimal wear, thus ensuring consistent positioning. The wheels, which are approximately 80mm in diameter, are pressed against the rails under spring pressure but the design ensures no flat spots on the outer rolling surface. The devices will be used in the next generation of high speed elevators by the world's leading manufacturers. Jesa makes bespoke over-moulded bearings of various different kinds, including bearings with over-moulded chain sprockets, quiet running surfaces and belt pulleys for both vee and flat belts. The company also sells ball bearings with shaft sizes from 2mm to 50mm. TS For more information and to enquire online, visit www.eurekamagazine.co.uk Jesa UK Enter XXX Pointers * Wheel sensors to determine exact lift cabin position can be improved by incorporating a double row ball bearing in a hard plastic wheel, and over-moulding this with a softer thermoplastic tyre. * The hard plastic maintains rigidity and reduces noise while the softer tyre ensures adhesion and reduces wear * The manufacturers also produce a range of other over-moulded products including chain sprockets and belt pulleys