28 replies to this topic

[skierdude9450]

I was riding the Bridger Gondola yesterday, and I noticed something interesting that was on three towers. On the uphill side there were 6 sheaves and on the downhill side there were 8. This was also on the old Summit Express @ MJ. Can anyone please explain this to me.

[liftmech]

The amount of sheaves on any given tower is dictated by the loading on that tower. For example, a lift that is not going to load anyone going down will have less sheaves on the 'light side' because the carriers that pass over them are empty. On the other hand, a lift that has downloading wihll generally have the same or nearly equal number of sheaves on both sides of the towers. This is why you'll see towers on certain YAN installations that have no sheaves at all on the light side, such as Loveland's Chair 1. The same concept works in reverse for a depression tower; you might see 6 hold-down sheaves on the heavy side and 8 on the light because there is more weight (hence the name) on the heavy side and less need for sheaves to deflect the rope.

[skierdude9450]

But that still doesn't explain why there would be more on the loaded. I've never seen anyone download the Bridger Gondola, and these are regular sheaves; not deflectors.

This post has been edited by skierdude9450: 03 April 2006 - 01:26 PM

[coskibum]

i think what liftmech is pointing out is this,



for example, this doppelmayr lift is only designed to down load every 4th chair, 4 chairs max. now every chair can be loaded going up. hence there are more sheaves on the uphill since there is a larger passenger load then the downhill side. is this what you were asking?

[Peter]

I think he is saying that there are more sheaves on the DOWNHILL non loaded side.

[liftmech]

I'd have to see a picture of what you're talking about. I've never seen a 'regular' tower with more sheaves on the light side than on the heavy. It's got to have something to do with the lift profile. I don't recall the first Summit lift having a tower with that configuration, either.

[lastchair_44]

are the sheaves the same size?
for instance...are the sheaves on the uphill side bigger than the sheaves on the downhill side?

[skierdude9450]

Skier, on Apr 3 2006, 07:28 PM, said:

I think he is saying that there are more sheaves on the DOWNHILL non loaded side.

Thats exactly what I'm saying. There are more on the NON loaded side; the downline side. I'm well aware of how in that picture of Thunderhead Express there are less sheaves on the non-loaded side, that's very common, but Im saying the exact opposite. The sheaves appear to be the same size. If anyone is familiar with the old Summit express, I think that it was on tower 11, near the top of Pony Express. On the Bridger Gondola, I think that the first one is around the first set of depression sheaves. I wish I had taken a picture of that, but I'm back in Denver now and Jackson Hole's closed, and Summit Express is no longer.

This post has been edited by skierdude9450: 04 April 2006 - 06:50 PM

[liftmech]

In lieu of a photo, can you describe the terrain/profile features in those towers' general area? I'm trying to get a sense of what you're asking since my earlier posts describe the rare instances I've seen of more sheaves on the light side.

[chuckm]

what bridger gondola are you talking about?

[Peter]

I assume he's talking about the Bridger Gondola at Jackson Hole, that's the only Bridger Gondola that I know of.

[skierdude9450]

The terrain is moderate, not very steep at the first one, then the the next two are about an easy black; around 20 degrees.

[liftmech]

Are you by chance referring to a combo tower, where there are sheaves on both sides of the rope?

[skierdude9450]

You mean compression assembely-nope.

[iceberg210]

Part of it may be the pathway the downhill gondolas will be running. For example on a couple of the Yan's in which the downhill side would be beamed up in the air and not be supported by any towers over a certain length there are more sheaves on the downhill side because it needs to change the angle of the rope more then on the uphill side. That's the only real reason I could think of.

[liftmech]

skierdude9450, on Apr 9 2006, 12:34 PM, said:

You mean compression assembely-nope.

No, I don't mean compression assembly. Compression/depression/hold-down- all the same thing in industry parlance.

I'm stumped onthis one; I've listed allthe reasons I can think of for why there would be more sheaves on the light side and apparently none of them fit this instance.

[Outback]

Hey Chuck-em
(now thats funny!)
Think there is a bridger gondola in Penciltucky.
I will check my map out.
Heading to Missouri next week to work on a sight-seeing lift on the Mississippi River.
Bringin my banjo and a fifteen inch crescent.

[chuckm]

OK- OK - ya never know- some of these lifts are named the same. Towers 9 and 12 on our gondola have 6 wheel supports on the heavy side and 8 wheelers on the light side - this is due to loading conditions- mainly a fully loaded downhill with an empty uphill- the load is much higher on the lightside than with the same condition on the uphill side.
good luck down there, don't try to swim with that shifter!

[Peter]

The Bridger gondola will be used for sightseeing once the tram closes, so there will be downloaders then.

[chuckm]

Yes, and we will be downloading the construction workers for the new restaurant and then an evening non skier restaurant operation as well. the lift is set up for 100% downloading. We will also be upgrading the capacity this summer with 18 new cabins to bring us to the design cap of 2400 pph.