The London Olympics began with an impressive opening ceremony. 62.000 spectators in the stadium and billions of people live on television were able to follow, among other things, the development of England from agricultural land to an industrial nation. In this scene, six industrial chimneys grow out of the ground incredibly fast. Permanently slipping, frictional safety clutches by Mayr Antriebstechnik offered an olympiareife performance.
The Dutch company Inventeq was commissioned with the staging of this illusion. The aim was to create the impression that the chimneys, which had been sunk first, rose out of the ground like massive walls. In fact, the 36 m were tall chimneys made of printed fabric. In order to stabilize the fabric hose when pulling up, the outer skin was tightened with several blowers and the wire rope to pull up the chimneys with two counter-rotating winds stabilized.
While a winch pulled up the upper frame of the chimney, the drive of the second winch in the base of the chimney ran at a relative speed against the pulling direction, keeping the wire taut. The differential speed between both winches of maximum 60 min-1 was compensated by permanently sliding, friction-locking safety clutches from Mayr. The resulting thermal stress was a real challenge for the design and design of the safety clutches and required Olympics-ready performance.
The clutches had to slip for about 30 s with a torque of 1100 Nm. Standard designs would not have been able to cope with the enormous frictional losses of around 7000 W. In order to use the friction clutches under these conditions, a special heat sink was developed and flanged to the output element. In addition, the heat flow from the friction linings to the output element was optimized via an adhesive bond. These measures lowered the temperature to such an extent that the frictionally engaged safety clutches could reliably meet the high requirements of the Olympic opening ceremony.