12 replies to this topic

[KZ]

Ok, im kinda cold on this stuff, but when the doppelmayr grip goes in the terminal and lets go of the rope, is there a spring in the grip that keeps the clamps open? At sierra you can look up and see that nothing is holding the grip down, so i was wondering how this worked

Also, do other grips (mainly the poma) have the same system as doppelmayr, or is there something holding the grip open?

[SkiBachelor]

I think the Poma's older grip design worked like a pen, where you push down on the top cap to push the pin out and then push it again to make the tip go back inside. I could be wrong, but I think it worked as that type of concept.

[floridaskier]

I think you're right, Cameron. I've watched the Tombstone Express terminal (it doesnt have the brushes) and the little metal rod that sticks out from the bottom of the spring isn't sticking out nearly as far when it''s inside the terminal as it is on the line. When the grip is being re-attached, the metal rod sticks way far down, then comes back up but not as far as it did before. I assume this is because the grip closes farther because the haul rope is in the way.

If that didn't make the slightest bit of sense, I'll try to draw a picture of it

[floridaskier]

I think the Doppelmayr grip locked into place. It locked around the haul rope, then was unlocked by the detachment rail, then just sorta hung there as it went around the terminal, then was re-locked when it left the terminal. The old CTEC grip worked the same way. There was a small rubber-looking spring inside the grip that you can see when you look up on the CTEC detachables up until 2001.

Again, if this didn't make any sense, I'll draw a picture

[lastchair_44]

the AK 4.0 and AK 4.1 detach grip springs from GaraventaCTEC are actually bellvill washers stacked opposing each other. there are 14 of them.

[floridaskier]

I was close

[Kelly]

Detachable grips gripping

All grips have a spring as source of energy to grip the haul rope. The spring source could be rubber, cupped washers, coil springs from the front suspension of a Chevy truck, etc. On some grips you may not see the spring system because of an exterior housing that protects the springs from weather and dirt contamination.

A simple explanation is to imagine a pair of scissors; the pointy end grabbing the rope- and your hand acting as the spring force to pivot the blades to grab the rope.

Detailed explanation-
As the grip enters the terminal they:
Are captured by tapered guides
Springs are compressed
The grip jaws open away from the haul rope
Grip is decelerating
Grip is raised above or to the side of haul rope
The spring is released
Grip jaws close
Grip is moving to position itself in conveying system guide track(s)
Grip is matched to conveying system speed
Grip is captured by conveying system
Grip is conveyed to other side
Springs are compressed
Repeat as necessary

Needless to say detachable lifts are high maintenance items.
See other topics on detachables and YAN grips for added information.

Ryan B

[floridaskier]

Wow Ryan you really know a lot about lifts

[liftmech]

Poma's grips have never locked open in the terminal as far as I know. Doppelmayr likes to have his grips lock open ('over-centre') for some reason, and CTEC does the same. All grips, regardless of manufacturer, have at least a few pounds of pressure inthem even when they're not on the rope. Otherwise, they'd flop around a bit too much and not have any tolerance for rope shrinkage or grip wear. Tyler- you're right about the 'little metal rod' sticking out farther when the grip is on line. That's called the 'spring guide rod' (at least on Poma TB-41s) and it is attached to the top spring cap. Say the rope is 41mm (hence the 'TB-41') then the grip closes to 41mm online and less in the terminal- so the springs are extended more in the terminal than on line.

[liftmech]

I forgot to answer the question about Doppelmayr grips.
No, there is no spring keeping the grip open. Rather, the linkage between the mobile jaw (the part that moves) and the spring guide rod has a slot in it that allows the linkage to sit in one of two positions. The bottom of the mobile jaw has a spur that is pushed up and back by a plastic track in the terminal, and that locks the grip in the 'open' position. When the grip moves around to the other side, the track does the same thing only this time it is to the 'closed' position.

[SkiBachelor]

Outgoing Doppelmayr Grip. Notice the plate sensors.

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[liftmech]

Looks like Doppelmayr finally put switches rather than brittle bars in his terminals. It's about time... if you had an ice chunk in the terminal and it hit the bar, you'd have to replace it rather than just moving a switch back into position. Rather costly, but I suppose he had his reasons.

[Dave]

KZ, on Nov 8 2003, 11:42 PM, said:

Ok, im kinda cold on this stuff, but when the doppelmayr grip goes in the terminal and lets go of the rope, is there a spring in the grip that keeps the clamps open? At sierra you can look up and see that nothing is holding the grip down, so i was wondering how this worked

Also, do other grips (mainly the poma) have the same system as doppelmayr, or is there something holding the grip open?
<{POST_SNAPBACK}>

On the doppelmayr the springs are depressed on a downward slopeing rail. The rope "cable" that has just left the PTO 'power take off' falls from the flat plane of the guide rails that the small wheels on the chair ride in. This is done by a tilt of the bull wheel that is fixed lower than the guide rails. As the chair passes the depression rail the grip is allowed to close onto nothing. Thus the name detachable the pto run the tires that push down on to the traction plate which is the black grate next to the springs first the deceleration array this is a straight line of wheelbarrow sized tires that turn progressively slower until you are near the unload point the chair will make the turn and then reveries the whole prosses