System Müller
The Müller system is a system for detachable monocable gondolas . The central component, the Müller clamp, was one of the first automatically operated, detachable rope clamps for circulating cable cars, which was developed by the Swiss engineer Gerhard Müller towards the end of the 1940s. In contrast to the separation between the carrying cable and the pulling cable that was common for gondola lifts at the time, as was the case with the Wallmannsberger system from 1947, lifts equipped with the Müller clamp only need a single wire cable . The clamp makes it possible to automatically detach the cabin or chair in the station from the rope, to slow it down and thus to offer the passengers a comfortable entry without reducing the speed of the hoisting rope and thus the rest of the train.
The first lift equipped with the Müller-Klemme was the Sattel -Hochstuckli chairlift from 1950, which only had to be replaced in 2005. The first gondola lift with the typical aluminum gondolas started operating in Brig in 1954 . The companies Girak in Austria , Weber in France and Taihei Sakudo in Japan built railways with Müller technology under license. It was not least the relatively uncomplicated and inexpensive technology that led to the fact that gondola lifts based on the Müller system became widespread worldwide. The last cable car with Müller-Klemme is the Guia Cable Car in Macau , built in 1997 .
Working principle
The Müller clamp is a screw clamp and is closed and released via a drive gear (colored red in the picture).
When coupling, the vehicle, rolling on the station rollers of the cable clamp on the hanging rail, is brought over an inclined plane to the height of the cable and accelerated (gravitational acceleration) until the clamp opening of the device rests on the cable. The vehicle is taken along by the rope with the clamp still open. When the closing process now begins, the drive gear passes a rack with rack teeth mounted on the hanging rail . When the gear wheel rolls along the stationary rack, a threaded spindle is turned and axially shifted inside, which presses the clamping jaws shut and thus fixes the clamp on the rope until the defined clamp pressure is reached. As soon as this terminal pressure is reached, a slip clutch arranged between the gear wheel and the spindle comes into action and prevents the threaded spindle from being tightened too tightly. An additional disc spring package, which is housed in the distinctive cylindrical housing, prevents the clamp from loosening during operation if the self-locking of the clamping thread is insufficient.
The uncoupling from the hoisting rope is done according to the same principle, only that at the uncoupling point the rack is attached on the opposite side as at the coupling point, whereby the unrolling gear is rotated in the other direction. The clamping spindle is opened again by the rotary movement. The slip clutch is bypassed when uncoupling to ensure that the clamping spindle is screwed on in any case. Finally, the vehicle, rolling again with its station rollers on the ascending hanging rail, is lifted from the conveyor rope that continues to run and decelerated to the station speed.
In newer railways, in addition to the inclined plane for accelerating and decelerating the vehicles in the stations, tire conveyors were also used in order to meet changed legal requirements. Since the regulations at the time in Switzerland only allowed two people to be carried per rope clamp, two clamps connected to one another by means of a joint were usually used on gondola lifts.
Competition systems
In the 1950s, several clamp systems for detachable single-cable gondolas competed with the Müller-Klemme, many of which were manufactured under license by other cable car manufacturers across Europe . The most important of these:
- VR 101 from Von Roll : spring / gravity coupling, mainly used on chairlifts . Was used to couple the gondolas of the former Jennerbahn in Schönau am Königssee.
- Giovanola clamp: Gravity clamp, used by WSO , PHB and Habegger , among others
- Carlevaro & Savio clamp: spring clamp used by Carlevaro & Savio and under license from Heckel and Agudio.