12 ms·

Related: how can a gondola move slower or stop while it is on/offboarding without stopping the rest of the cars?

ilyagr 5y ago
Every time a gondola car arrives to the station, it is detached from the main cable and put on a slower cable (or a belt?). I wish I knew the exact mechanism that makes this work reliably.
- a-dub 5y ago
  they detach and then roll on a series of rubber wheels that decelerate wheel by wheel on the way in and accelerate on the way out. the grip itself is spring loaded and the spring force is measured every time the grip passes through a terminal. if a grip is weak, the lift stops. if you look closely at a detachable grip, you'll see two wheels. those go into a funnel that squeeze open the spring loaded grip to release the haul rope. the chair or gondola cabin then is guided with one of those wheels while powered by the 20 or so small rubber wheels mentioned above that move the chair through the terminal. reattachment works the same, the wheels progressively speed up to the haul rope speed (5-6 m/s) as the funnel opens releasing the grip to snap back onto the haul rope. position sensors throughout the terminal and at the towers stop the lift if anything is out of position. (or a grip is weak, as mentioned above) and like any safety critical reliable system, a lot of hardworking humans check the system regularly.
- snowytrees 5y ago
  while not necessarily on how gondolas work, this is a great documentary on the engineering and design behind the peak2peak gondola at whistler: https://www.youtube.com/watch?v=xEAJmxe27h0 https://www.youtube.com/watch?v=xEAJmxe27h0
- jffry 5y ago
  Maybe there are other mechanisms, but the one shown in [1] seems pretty simple. The top of the gondola arm has a flat spot, and there are both wheels and the cable mechanism on the underside. In the station it detaches from the cable and just rides on the flat track, and then motor-driven tires push on the gondola to propel it at a controlled speed through the station. [1] https://youtu.be/589uRMy4Ty4?t=222 https://youtu.be/589uRMy4Ty4?t=222
herdrick 5y ago
https://www.google.com/search?q=detachable+ski+lift+mechanism https://www.google.com/search?q=detachable+ski+lift+mechanis...
snowytrees 5y ago
chairs/gondolas detach from the primary rope that carries them up/down the slope. So while the primary rope is moving the same fast speed, the chair isn't attached to that rope anymore. This is what allows detachable lifts to go so much faster than fixed (non-detachable lifts), the speed of them isn't dependent on people being able to board. If a ski resort wants to speed up their fixed grip chairs without spending the money on a detachable, they will use a loading carpet to move up the max speed of loading people (see: https://liftblog.com/2016/01/02/the-loading-carpet-solution/ https://liftblog.com/2016/01/02/the-loading-carpet-solution/)
- scoot 5y ago
  Despite what the OPs video suggests, there are no ropes used, rather steel cables. A rope's mechanical properties wouldn't be beneficial for a ski lift.
  - anamexis 5y ago
    No, rope is correct. Wire rope, more precisely. https://en.wikipedia.org/wiki/Wire_rope https://en.wikipedia.org/wiki/Wire_rope
    - Waterluvian 5y ago
      So is “rope” just any cord or any material that’s been braided or wound from many smaller cords?
      - johnwalkr 5y ago
        The terms are largely interchangeable but “wire rope” is the engineering term for cable used to transmit forces. Depending on who you ask it may only strictly refer to wire rope made from multiple bundles of strands.
    - scoot 5y ago
      You're correct - a wire rope is a cable, but a synthetic rope is not. But "rope" generally refers to synthetic rope, not wire rope, so a rope is not a cable.
teeray 5y ago
The cabins are detachable from the cable. The two terminals coordinate timing so that you don’t end up with a pile up. Occasionally you can see the lift automatically stop a chair at the base to adjust timing.
bujak300 5y ago
Either it is detaching from the cable or there is a "conveyor belt" for boarding on some simpler chairlifts
amalcon 5y ago
Detatchable chairlifts have always amazed me. They're definitely one of the bigger quality-of-life improvements that alpine skiing has ever seen. Not only do they let you ski more, but they also help keep you warm (any skier will tell you that the chairlift is always the coldest part) and increase the effective throughput of the lift. The truly amazing thing, though, is the safety record: they have a mechanism to switch from a fast rope to a separate, slow rope and back. This transition (and, indeed, the grip on the rope) manages to have an excellent safety record despite being relatively complicated and dealing with snow and ice.
- Akronymus 5y ago
  Over here, chair lifts often have a cupola you can use to shield you from most of the wind and that keeps you decently warm (After about 2 minutes when your body heat warms it up enough)

Every time a gondola car arrives to the station, it is detached from the main cable and put on a slower cable (or a belt?). I wish I knew the exact mechanism that makes this work reliably.

a-dub 5y ago
they detach and then roll on a series of rubber wheels that decelerate wheel by wheel on the way in and accelerate on the way out. the grip itself is spring loaded and the spring force is measured every time the grip passes through a terminal. if a grip is weak, the lift stops. if you look closely at a detachable grip, you'll see two wheels. those go into a funnel that squeeze open the spring loaded grip to release the haul rope. the chair or gondola cabin then is guided with one of those wheels while powered by the 20 or so small rubber wheels mentioned above that move the chair through the terminal. reattachment works the same, the wheels progressively speed up to the haul rope speed (5-6 m/s) as the funnel opens releasing the grip to snap back onto the haul rope. position sensors throughout the terminal and at the towers stop the lift if anything is out of position. (or a grip is weak, as mentioned above) and like any safety critical reliable system, a lot of hardworking humans check the system regularly.
snowytrees 5y ago
while not necessarily on how gondolas work, this is a great documentary on the engineering and design behind the peak2peak gondola at whistler: https://www.youtube.com/watch?v=xEAJmxe27h0 https://www.youtube.com/watch?v=xEAJmxe27h0
jffry 5y ago
Maybe there are other mechanisms, but the one shown in [1] seems pretty simple. The top of the gondola arm has a flat spot, and there are both wheels and the cable mechanism on the underside. In the station it detaches from the cable and just rides on the flat track, and then motor-driven tires push on the gondola to propel it at a controlled speed through the station. [1] https://youtu.be/589uRMy4Ty4?t=222 https://youtu.be/589uRMy4Ty4?t=222

herdrick 5y ago

https://www.google.com/search?q=detachable+ski+lift+mechanism https://www.google.com/search?q=detachable+ski+lift+mechanis...

snowytrees 5y ago

chairs/gondolas detach from the primary rope that carries them up/down the slope. So while the primary rope is moving the same fast speed, the chair isn't attached to that rope anymore. This is what allows detachable lifts to go so much faster than fixed (non-detachable lifts), the speed of them isn't dependent on people being able to board. If a ski resort wants to speed up their fixed grip chairs without spending the money on a detachable, they will use a loading carpet to move up the max speed of loading people (see: https://liftblog.com/2016/01/02/the-loading-carpet-solution/ https://liftblog.com/2016/01/02/the-loading-carpet-solution/)

scoot 5y ago
Despite what the OPs video suggests, there are no ropes used, rather steel cables. A rope's mechanical properties wouldn't be beneficial for a ski lift.
- anamexis 5y ago
  No, rope is correct. Wire rope, more precisely. https://en.wikipedia.org/wiki/Wire_rope https://en.wikipedia.org/wiki/Wire_rope
  - Waterluvian 5y ago
    So is “rope” just any cord or any material that’s been braided or wound from many smaller cords?
    - johnwalkr 5y ago
      The terms are largely interchangeable but “wire rope” is the engineering term for cable used to transmit forces. Depending on who you ask it may only strictly refer to wire rope made from multiple bundles of strands.
  - scoot 5y ago
    You're correct - a wire rope is a cable, but a synthetic rope is not. But "rope" generally refers to synthetic rope, not wire rope, so a rope is not a cable.

teeray 5y ago

The cabins are detachable from the cable. The two terminals coordinate timing so that you don’t end up with a pile up. Occasionally you can see the lift automatically stop a chair at the base to adjust timing.

bujak300 5y ago

Either it is detaching from the cable or there is a "conveyor belt" for boarding on some simpler chairlifts

amalcon 5y ago

Detatchable chairlifts have always amazed me. They're definitely one of the bigger quality-of-life improvements that alpine skiing has ever seen. Not only do they let you ski more, but they also help keep you warm (any skier will tell you that the chairlift is always the coldest part) and increase the effective throughput of the lift. The truly amazing thing, though, is the safety record: they have a mechanism to switch from a fast rope to a separate, slow rope and back. This transition (and, indeed, the grip on the rope) manages to have an excellent safety record despite being relatively complicated and dealing with snow and ice.

Akronymus 5y ago
Over here, chair lifts often have a cupola you can use to shield you from most of the wind and that keeps you decently warm (After about 2 minutes when your body heat warms it up enough)