5 replies to this topic

[SkiBachelor]

Here is a video I found off of youtube.com showing a computer reenactment simulation of what happened when the haulrope derailed off a sheave assembly on a HSQ. I'm not sure if a carrier actually dropped or what since the live footage shows it still hanging, while in the model it shows it falling. The computer I'm on right now at school doesn't have speakers, but this movie is probably in German too.

http://youtube.com/watch?v=eC2w5s4ffHY

[sseguin613]

Little confused here. I guess it shows that if the haul rope falls inwards from the sheaves that the next chair would get caught and the rope would begin to slide through the grip and the chair could fall. But how could it fall inwards when most modern chairlifts have plates or guards or shields to physically block it from falling inwards. And if it fell outwards the cable catchers would most likely catch the rope, and it wouldn't get caught up and slide like it would in an inward deropement.

Are they refering to old style chairlifts? It doesn't look like HSQ grips to me but the animation is pretty crude.

Some insight would be appreciated.



p.s. The swinging forwards and back when the chair stops is kinda exaggerated. Quite a bit.

BUT IT IS A INTERESTING AND NEAT VIDEO.

[Allan]

They also seem to forget about deropement detection... but I guess it could be worst-case-scenario where the switches fail to detect the deropement or the circuit bypassed. I don't think a rope would slide through a grip very well either.. SSeguin you'r right - it would be fairly hard to have a complete deropement to the inside with the guards there (they are a requirement here and the US anyways) and rope catchers must be designed to permit the passage of grips.

[floridaskier]

I don't see how this would have happened without something happening first. Did the chair actually fall off, or was that just an animation done for the video? Seems unlikely that none of the safety circuits on a newer Doppelmayr (I think) HSQ would have caught it, and that the rope would slide through the grip behind the sheaves

[Jonni]

This puzzles me, because of the safety switches. Looking at that video it looks as if the cable deroped inward rather than outward, where the only thing that possibly in the slightest could have made those safety switches fail would be the cable ripping them off of the sheave assembly or cutting through the wires connected to them. Even then that idea still doesn't work because if the switches were working in this instance they would have tripped before the cable had a chance to cut through or pull off the wires. The animation doesn't really seem realistic without these ideas taken into consideration. The only other possible option would have been if the tower safeties had been bypassed that day.

My other question would is how could the chair/grip fall off of the cable? If this is a detachable lift, which I'm assuming it is, how would the spring or springs fail by way of the grip sliding along the cable as it's forced against the crossarm? I can't really believe that the grip doesn't have enough force on the cable to act more on the crossarm and the hanger bar than to cut through the grip itself. It just doesn't seem realistic to me.

[Allan]

Even if the switches and wiring was ripped apart - the lift would stop because of that.