How Long Does a Haul Rope Last

LiftGuy

ski_it;c-49230 wroteWe’d need Newplylong or lift guy, etc to answer that. My uneducated guesses are the tolerances aren’t too too tight. They could align the sheeve asy with a transit and make other adjustments once the threading or pull rope is on. ??

That's a good guess. While absolute precision isn't required, the need for quality alignment has increased due to the fact that a modern 6 place detachable will have much higher tension (48K-60K), larger diameter haul rope (up to 2") and fewer towers (20+/-) on the same alignment as M1. Initial alignment starts with pre-assembly in the parking lot. The line gauge (distance between the haul ropes) needs to be established as the sheave assemblies are installed on the cross arms- this can be done with a tape measure. The next thing is to ensure that the installed tower is plumb and on center-line. Once the cross arm is installed, you should have "rough alignment".

LiftGuy

newpylong;c-49232 wroteOh I think Liftguy is gonna be the person to answer this one fully. In my limited experience with installs, the surveyor did their thing (assuming a transit, they need line of sight) to place the stakes for the terminal and tower locations. We then dug our footing holes at those locations and the outfit doing the forms built them within the hole at those locations. When the towers are placed they are not perfect, the sheave trains can be adjusted to a certain degree left to right to make up for some degree of departure. Then minute adjustments are made after the haul rope is placed, and before hanging the carriers.

Probably some other steps he can add.

You got this! One thing I'll add is after the towers are installed, we would send technicians down the line, climb each tower, make sure all Heli rigging, restraints and obstructions are removed from the tower and sheave assemblies, then visually sight the downhill sheaves to the center of the next assembly as our 'rough alignment'. This gave us the confidence that the haul rope would not de-rope during installation. After the rope was spliced we would bump the lift a short distance, walk the line to see if we had any gross misalignment, and then run the lift slow and align each tower again. Once the carriers were installed we would once again check all the assemblies for plumb and alignment.
Hope this helps.

LiftGuy

lotsoskiing;c-49234 wroteWhat is the actual process for putting on the haul rope? Start with a string and hike up, climbing every tower and putting over sheaves, then move to thicker rope? How do they then pull the cable around? Need some serious power and a lot of bodies.

To start with a small cable (9/16"-3/4"- depending on the size of the main rope) is pulled downhill from the top terminal and manually placed over each cross arm...one for each side! This takes lots of bodies. The two ends at the top are then spliced together and at the bottom one end is spliced in to the main rope and the other is attached to a winch or other pulling device and winched around, tensioned and tied off, spliced and then released and reinstalled on the towers.
If you're interested, check out "riggingspecialties.com"- a specialty company owned by a friend of mine in Canada. Does a lot of "interesting" rope work- from cable supported suspension bridges to the Metro Gondola in Mexico City!

LiftGuy

Didn’t mean to kill this thread. I thought it might promote some more questions…

skelley19

I enjoyed your insight LiftGuy. How do they determine when it is time to replace a haul rope? I assume at least part of it is based on amount of stretch. What sort of NDTs are performed on haul ropes?

ceo

I have a question, though it might be a stupid one. Why do compression towers have lifting frames?

NewEnglandSkier13

ceo;c-49276 wroteI have a question, though it might be a stupid one. Why do compression towers have lifting frames?

I believe they are primarily used to hoist the sheave assembly and other parts onto the tower.

ski_it

Thanks LiftGuy. I’ll probably have questions later if others don’t ask them first

newpylong

NewEnglandSkier13;c-49278 wrote
ceo;c-49276 wroteI have a question, though it might be a stupid one. Why do compression towers have lifting frames?
I believe they are primarily used to hoist the sheave assembly and other parts onto the tower.

Also come alonging the haul rope up off of the sheaves for replacement/ maintenace.

TomWhite

Sam, the compression tower reminds of Black's triple. The 3rd-4th tower is very tall. At many areas that would be a compression/depression tower. It would be lower, out of the wind and easier for rope evac. Do you know why it isn't?

conrad

TomWhite;c-49285 wroteSam, the compression tower reminds of Black's triple. The 3rd-4th tower is very tall. At many areas that would be a compression/depression tower. It would be lower, out of the wind and easier for rope evac. Do you know why it isn't?

I don't have any insider knowledge, but I guess having the tall tower (s) there saved money on initial construction cost and maintenance costs by reducing the number of towers / sheave wheels needed overall. Again I don't have any exact information on the difference, but I believe Europe has a lower limit on chairlift tower height and Japan may be the strictest of them all. I'm not sure if ANSI has an upper limit on tower height. edit: limit on chairlift tower height.

NewEnglandSkier13

TomWhite;c-49285 wroteSam, the compression tower reminds of Black's triple. The 3rd-4th tower is very tall. At many areas that would be a compression/depression tower. It would be lower, out of the wind and easier for rope evac. Do you know why it isn't?

Tower 4 is extremely tall. It is a combination tower and like Conrad said, I'm sure it was just the cheapest option. We have almost no issues with wind.

LiftGuy

skelley19;c-49274 wroteI enjoyed your insight LiftGuy. How do they determine when it is time to replace a haul rope? I assume at least part of it is based on amount of stretch. What sort of NDTs are performed on haul ropes?

Good question. Haul rope replacement criteria involves various factors, mainly loss of nominal diameter, elongation of the lay length of the strands and X number of broken wires in a specified distance resulting in loss of "cross section metallic area" (a complicated formula relating to the main wires in the rope). Other factors include corrosion, wear and condition of the rope's core material.
As for NDT, Visual inspections are required every year. This includes visually inspection the entire length of the rope at slow speed, multiple measurements of rope diameter and lay length at random intervals, and close inspection of each of the tucks in the rope splice area. MRT (Magnetic Rope Testing), which can "see" into the interior of the rope, is required every three years and can be required more frequently by the rope manufacturer or a qualified rope inspector.

LiftGuy

ceo;c-49276 wroteI have a question, though it might be a stupid one. Why do compression towers have lifting frames?

From a manufacturing stand point, making the cross arms all the same helps in production, shipping and assembly.
From an Operators standpoint, the lifting frames on compression and combination towers can be used for raising and lowering the sheave assemblies and other components for maintenance purposes. It also provides a tie-off point for the technician's fall protection equipment.
From an esthetics standpoint, it makes them all look the same!:-)

skelley19

Thanks LiftGuy. Ragged had a cool video on their instagram yesterday showing magnetic particle inspection being conducted on a chairlift grip.

TomWhite

NewEnglandSkier13;c-49289 wrote
TomWhite;c-49285 wroteSam, the compression tower reminds of Black's triple. The 3rd-4th tower is very tall. At many areas that would be a compression/depression tower. It would be lower, out of the wind and easier for rope evac. Do you know why it isn't?
Tower 4 is extremely tall. It is a combination tower and like Conrad said, I'm sure it was just the cheapest option. We have almost no issues with wind.

Thanks.

Remski

Went to Mcintyre today to checkout the Hill bar and grill and to my surprise they’re working on new ropes for the chairlifts from what I gathered from the spools of cable in the parking lot. The Bar and Grill are open in the off season with outdoor dining, entertainment and lawn games.

slatham

So how might Magic's new Black lift have been engineered and/or installed incorrectly? They now need 2 new sheave assemblies to rectify, one of which has to be manufactured to spec.

newpylong

So for a used lift the engineer will take the inventory of towers (and their accompanying lengths) and the available sheave trains (paying special attention to types: regular, compression and depression) and try to make it fit the lift profile. I am not an engineer but in general it needs to not hit the ground if 1 tower de-ropes, no towers can be overloaded (overtensioned), etc and so on.

Not sure of the exact circumstances but obviously reality did not align with the modelling once they began to hang the carriers on it.

I know of one fairly recently installed lift with a tower out of alignment (beyond the margin of adjustment) due to being set incorrectly, but nothing as bad as what seems to have happened here.

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