41 replies to this topic

[Duck]

liftmech, on Mar 6 2005, 11:05 AM, said:

You're a mechanically inclined guy, right? Think of it this way: Friction works in many ways. Your car does not slide back down a steep hill because of the friction between the tyres and the road surface. Yan used that principle in his grips, so that in the final equation for grip force 400 or so pounds was actually the weight of the carrier resting on the haul rope. Now, when a chair bounces (as they will on a sudden stop) the carrier weight is removed from the equation when it reaches the top of the oscillation. Make sense?
<{POST_SNAPBACK}>

So you're saying there *was* no grip, it just sat on top of the rope?!

The only way I could see him designining it is if he'd had it mechanically set up so that the actual force of the chair pulling down is set up to cause the grip to clamp tighter, through a linkage. (Thinking the same way a wedge-type elevator safety brake works or a cam and fin antirollback brake like you find on some coasters, where the stronger the load, the higher the retention force).

-Iain

[SkiBachelor]

Here is the protype YAN Type 7 grip. As you can see, this wasn't the grip design that was used on any of LE's HSQs.

 type7a.jpg (17.26K)
Number of downloads: 210

[Duck]

Oh, jeez. Okay, that's scary. I totally see what you're talking about now. Take the load off it and you've got no grip retention force on the two jaws.

-Iain

[poloxskier]

Thats the same idea behind some of Von Roll's eary detachable grips isn't it? Just the force of gravity holds it on the rope?

This post has been edited by poloxskier: 06 March 2005 - 08:34 PM

[Duck]

From that image, you can see how the load coming from the hanger (from the chair, gondola cabin, whatever) is pulling down on the pivot point for the two jaws, which are seated on the rope. So you've got a mechanical advantage there... but if you take away the load, there's effectivley no grip force. Crazyness!

A simple solution to this, to me, would be to put a compression spring between the compression rollers for the two jaws, no?

By Von Roll, if you mean like the gondola at Cedar Point, I'm almost sure there's some kind of spring-loaded bistable mechanism in their grips. When they attach or detach from the line it sure seems that way, by the way the rope snaps in and out of the grip. Of course, I've never had one of the things apart, and it's hard to get close enough to see, but that's what it looks like, anyway. :)

-Iain

[crazyskier91]

Vonrolls V-101 grip is baically like Doppelmayrs DS-104.

[Duck]

Uh, okay. :)

What is a Von Roll V-101, and what is a Doppelmayr DS-104?

-Iain

[liftmech]

The DS-104 is the older of the two common Doppelmayr grips, and I'm not sure fwhat a VR-101 is aside from a von Roll grip.

I think the gravity aspect of Yan's grips is being overanalysed here. What I'm trying to describe is this: The grips were clamped to the rope by two mobile jaws; they were held in place by two rubber springs. The springs provided almost all the grip force. The weight of the carrier, with no complex linkage as Duck has mentioned, provided the rest simply through friction on the haul rope (the fixed jaw rested on top of the rope instead of being one-half of a clamp as it is on other grips). As I've mentioned before, this friction was negated any time the carrier bounced.

Here is a (poorly drawn) cross-section of the Type 7 grip. I've left off the traction plate and chair head axle, but the rest is shown.

Attached File(s)

•  type_7.JPG (37.58K)
  Number of downloads: 138

[Duck]

But look at what point the carrier is attached to. It's mounted to the pivot points for the jaws, so any downward force on the carrier itself aids the clamping force via a mechanical advantage.

I don't have time right now to model it up (I'm not working at my desk) but I'll try and do up a sketch of what I'm trying to explain...

-Iain

[Aussierob]

Unfortunately Doppelmayr have removed "conceptual inputs" from the web. It has excellent drawings and a description of the grip. It also has some equations showing how the force is applied. Liftmech has it right but its kind of hard to visualize if you haven't seen one up close.

[Aussierob]

OK, I scanned the relevant pages. I think this is legal as it was on the web at one time. Mods can remove it if they feel necessary.

Attached File(s)

•  conceptualinputs64.jpg (41.1K)
  Number of downloads: 150
•  conceptualinputs65.jpg (43.41K)
  Number of downloads: 119
•  conceptualinputs66.jpg (33.47K)
  Number of downloads: 100

[liftmech]

It's in a published book, as well as on the web, so I would think it's legal.

The more I look at that grip, the more questions pop up. Where would the traction plate be mounted? How much clearance was there when the grip passed through a depression assembly? the design looks pretty simple and straighforward but the application must not have been.

[Aussierob]

The traction plate is right in the centre above the rope The tyre or sheave then is centered between the operating arms. There is not a lot of clearance between the op arms and the station machinery.

I love this quote "many of the possible problems encountered on grips in general can be described on the basis of this grip construction." Says it all about Yan grips right there.

[floridaskier]

Could Yan grips go under depression sheaves, or is that why the terminal sloped up at the end?
The Yan HSQ at DV had one compression assembly (tower 11, I was 5 or so when they took it out and I remember that it was really bumpy) but it used a rack of little tiny wheels above the haul rope instead of normal sheaves, and (IIRC) regular ones on the bottom. Anyone remember those?

[liftmech]

Revisiting the topic-
Yes, the YAN detachable grips could go under depression sheaves. The needles were actually split at the ends so that they would conform to the rope better than other manufacturers (not that anyone else has adopted this style in the years since the patent expired). The grip body was relatively flat as well, so that the passage under said sheaves was less abrupt. This actually made the grip wander in the sheave, since the shape of the grip was not there to hold the grip in the groove. Also, if you look at the photos of the grips that have been put up lately, you'll see that the traction plate is mounted on top of the hanger arm rather than the grip itself; the grip rollers were also mounted on the hanger arm.

[artfart]

wow interesting stuff, the only yan hsq i rode on was retrofitted by poma at mount snow and killington.
id be kinda nervous riding on a yan hsq with that grip.

[Superchairliftfan]

What's the patent # for the grip?

[yan lover14]

Why can't I view any of the pictures posted?

Patents for the grip: http://www.google.co...epage&q&f=false

[vons]

here is a link to a report of the last unmodified YAN HSQ in existence

http://www.remontees...rtage-1057.html

[yan lover14]

vons, on 13 March 2013 - 04:59 PM, said:

here is a link to a report of the last unmodified YAN HSQ in existence

http://www.remontees...rtage-1057.html

Except the chairs.