Curved tow lift
Curve tow lifts are ski lifts based on the Ernst Constam system , which pass one or more curves along their route in order to avoid obstacles on the direct route. This is associated with complicated constructions due to the construction of the hangers.
Problem
In the Constam system, the suspension arm does not grip the rope clamp from below, but from the outer side. Therefore, deflection sheaves, as they are necessary for curves, can only be driven on if they are on the inside of the rope. In the case of a curve, however, the downhill and uphill ropes must be deflected, so that a deflection disc would be necessary on the outside.
Ways to solve
Inclined roles
The easiest way to negotiate a curve is to tilt the rollers of a prop at a slight angle. However, only very small curve radii are possible with this. A further development of this system makes larger radii possible by alternately using support rollers and hold-down rollers and the support is longer.
Polygon lift
The polygon lift, an idea by Ernst Constam, can negotiate larger radii . The rope going uphill runs through a normal pulley on the inside, while the rope going downhill is guided into the valley on a separate route without diversions. Obstacles can occur on the descent because no passengers are transported on the descent anyway. The valley and mountain stations do not deflect the rope by 180 °, which makes the tensioning of the rope more complicated: If the pulley were pulled further back for tensioning, the rope would derail on the supports. Therefore, three deflection pulleys are used in the tensioning station, of which only the middle one is movable, the other two hold the rope in the correct position on the two stretches and thus prevent rope derailments. This principle is still widespread today, but more supports are required and so the cost of materials is significantly higher.
Because its cable guide often forms a triangle - namely when it has exactly one curve - the polygon lift is often also called a triangle lift.
Twisting curve
The twisting curve is a way of bypassing one deflection pulley on the outside with several on the inside. Here, too, the uphill rope travels through an ordinary pulley. The downhill cable, on the other hand, coming from the mountain station is first led straight across the curve to a deflection station that deflects it by 180 °. So it goes uphill again to the curve of the climbing rope and is deflected again there so that it is again parallel to the climbing rope and can usually be led to the valley station. This system is also relatively widespread and is still used today.
Bachmann curve
The Bachmann curve - also called the Baco curve after the manufacturer - uses a special deflection disc that can be driven on by hangers if it is on the outside. This pulley deflects the rope with the help of cams . If a hanger passes the pulley, these cams are pushed up and the outside of the rope can be driven over. Special hangers are required for this. This system allows as one of three curves in different directions on a single lift.
Double lift
The two-cable T-bar lift circumvents the problem of side-mounted hangers by having not one, but two ropes. These are run parallel, horizontally next to each other, the hanger arm grips between them so that the carrying and hold-down rollers can be used without any problems. In the curves and on the pulleys of the valley and mountain stations, the ropes are placed at an angle and are vertically above one another. The ropes are rotated in such a way that the hanger arm grips from the outside and curves can be negotiated in all directions. Because all roller batteries have to be available twice (once per rope), the maintenance effort is significantly higher than with other surface lifts. Today there is only one such two-cable drag lift on the Belalp in Switzerland.
T-bar lift with integrated rope guidance
Similar to the two-cable T-bar lift, the T-bar lift with integrated cable guidance also avoids the problem of the side-mounted hangers. Here the hanger arm grips the rope vertically from below. Curves can be negotiated in all directions, as can hold-down supports, the problem is with the support supports. Here, two angled roller batteries are used, one on each side of the rope. In addition to the unrestricted curve mobility, the very safe cable guidance on the support supports is an advantage, but as with the two-cable T-bar lift, the maintenance costs are considerably higher than with conventional T-bar lifts. The only lift still in operation is on the Swiss Engstligenalp , but without a curve.
Combinations of different curve systems
Several curve systems are rarely used in a lift. The (now replaced) Totalp ski lift in Davos, Switzerland, for example, was a polygon lift whose rope going down the valley was deflected again by a twirl curve.
Todays situation
Since surface lifts - especially in the Alps - are now often replaced by chairlifts , more and more curved surface lifts are being replaced. It is also rare that curve lifts are still being built, the latest is likely to be the Cuolm da Vi lift in Disentis , Switzerland, built in 2019.
Individual evidence
- ↑ www.bergbahnen.org • Seilbahnlexikon - history & technology. Retrieved August 1, 2020 .
- ↑ Curves - Skilift-info.de. Retrieved August 1, 2020 .
- ↑ remontees-mecaniques.net: Téléski à enrouleurs 2 places (TKE2) Hohstock - www.remontees-mecaniques.net. Accessed August 1, 2020 (French).
- ↑ www.bergbahnen.org • Cable car database - detailed view. Retrieved August 1, 2020 .
- ↑ www.bergbahnen.org • Seilbahnlexikon - history & technology. Retrieved August 1, 2020 .
- ↑ Davos - Parsenn - Gotschna • Old love doesn't rust • Enviadi. February 23, 2019, accessed on August 1, 2020 (German).
- ↑ [Archive] Cable Car Projects Switzerland 2019. In: bergbahnen.org. Retrieved August 1, 2020 .
- ↑ Cuolm da Vi-Parlet. Retrieved August 1, 2020 .