17 replies to this topic

[sseguin613]

How does a detachable chairlift test for grip force?

On doppelmayr DS grips, there is a small piece of metal that hangs down that is on the same moving part as the mobile jaw. Is this related? If it isn't in a certain position then it will hit the brittle bar and stop the lift? It can't be that simple.

I found this on the site:
Doppelmayr's Detachable 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.


If anyone has a picture and can show if what is being talked about here 'the spur under the mobilejaw' is that thing that hangs down under the grip?

How do pomas work for grip force testing?

This post has been edited by sseguin613: 10 March 2009 - 06:16 PM

[Kicking Horse]

On My Poma Grip Force testing is done as it detachs from the rope. On the compression rail is a red box with a sensor. It's either pass or fail. If it fails the lift shuts down.

[mikest2]

sseguin613, on Mar 10 2009, 07:11 PM, said:

How does a detachable chairlift test for grip force?

On doppelmayr DS grips, there is a small piece of metal that hangs down that is on the same moving part as the mobile jaw. Is this related? If it isn't in a certain position then it will hit the brittle bar and stop the lift? It can't be that simple.

I found this on the site:
Doppelmayr's Detachable 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.
That's how it works, the spring pack is compressed by the operating arm(on top) then the jaw tab is pushed up when opening, and down when closing. Grip force is indicated by the swivel dog, which is rotated by movement of the shift plate, which is mounted on the bottom of the secondary spring pack. So......if the primary belleville spring pack loses too much force, the secondary(coil spring) pack housing moves, making the swivel dog swing down and break the fork.
Yup.....it's that simple


If anyone has a picture and can show if what is being talked about here 'the spur under the mobilejaw' is that thing that hangs down under the grip?

How do pomas work for grip force testing?

A section of the opening/closing rail flexes, the amount of deflection gives a go/ no go value, similar to Leitner and Dopp DT's

[sseguin613]

The swivel dog, as you call it is the 'valve knob looking thing' viewed from the underside of the grip?

Does anyone have close up shots of the grip to confirm or label these parts so there isn't any confusion?

What locks the DT torsion grips open?

[LiftTech]

It doesn’t, it’s more like spring force testing.

sseguin613, on Mar 10 2009, 10:11 PM, said:

How does a detachable chairlift test for grip force?

On doppelmayr DS grips, there is a small piece of metal that hangs down that is on the same moving part as the mobile jaw. Is this related? If it isn't in a certain position then it will hit the brittle bar and stop the lift? It can't be that simple.

I found this on the site:
Doppelmayr's Detachable 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.


If anyone has a picture and can show if what is being talked about here 'the spur under the mobilejaw' is that thing that hangs down under the grip?

How do pomas work for grip force testing?

[shelldog]

sseguin613, on Mar 10 2009, 08:17 PM, said:

The swivel dog, as you call it is the 'valve knob looking thing' viewed from the underside of the grip?

Does anyone have close up shots of the grip to confirm or label these parts so there isn't any confusion?

What locks the DT torsion grips open?

Attached are some pics of the swivel dog in both positions

Attached File(s)

•  DS_GF_up1.JPG (562.42K)
  Number of downloads: 93
•  DS_GF_down_2.JPG (136.2K)
  Number of downloads: 89

[Lift Kid]

Oh!! Now this whole thing makes sense. Thanks Shelldog for those pictures. I never could tell before how the DS's could be tested for gripping force.

Now does anyone have pictures of the numerous things that lock the grip open, and release it to be closed again? Like the spurs and the plastic track that was referred to above?

[sseguin613]

Ok so in the posted pictures, the piece that is in 2 different positions in the centre of the picture is responsible for latching the grip in the open position or hitting the brittle bar if the main spring fails?

If it doesn't activate the lock, what in the picture does?

[mikest2]

sseguin613, on Mar 12 2009, 06:42 PM, said:

Ok so in the posted pictures, the piece that is in 2 different positions in the centre of the picture is responsible for latching the grip in the open position or hitting the brittle bar if the main spring fails?

If it doesn't activate the lock, what in the picture does?

The black plastic bit is the swivel dog (grip force) The metal spur on the right (in two different positions) is part of the mobile jaw, it slides up a plastic ramp in the station as the grip opens, as the operating lever(on top of grip, arm with roller) is released off the opening rail, the mobile jaw locks open over centre(as is picture) as the grip goes back onto the rope, the operating lever is depressed again and a plastic knife rail pushes the mobile jaw back down over centre(actually gravity does but sometimes the knife rail helps) if the operating lever does not for some reason open or close the grip, the ramp or the knife rail will

[liftmech]

Those who actually work on DTs can correct me if I'm wrong, but I believe they operate on the same general principle as the DS grips, where the jaw linkage allows the grip to lock open once it's in the terminal.

[SuperRat]

liftmech, on Mar 19 2009, 09:01 AM, said:

Those who actually work on DTs can correct me if I'm wrong, but I believe they operate on the same general principle as the DS grips, where the jaw linkage allows the grip to lock open once it's in the terminal.

This is true. When the operating arm is pushed down past over center the link will hold the jaw open. For the jaw to be closed the arm has to be pushed up briefly until the spring tension can finish the closing.

[SuperRat]

Apparently one of my predecessors forgot that an open DT grip is a like a mouse trap waiting to be sprung. Once while stripping a DT he chose to remove the operating roller before closing the jaw. The roller axle required some persuasion with a mallet so he hammers on it a couple of times then... *SNAP* ...the jaw closes and the whole grip stand jumps and falls over (I don't know why they hadn't bolted the table down before that) and he was lucky to be uninjured. The mishap served at least one purpose: the anecdote was shared with me and I've never forgot it.

[SuperRat]

This particular shop is connected to the lift by a parking rail. Anytime we put a chair with a DT on the ground we first pound a wedge between the arm the bridge to help keep the open until its in the stand.

[SuperRat]

The wedges are made of wood. The ones we are using now were shipped with our new '07 Doppelmayr CTEC. Eventually the wedges get hammered to death and we have to make new ones. We're lucky to have rails and shops at all of our detachables.

I'll take some pictures of our lifts and shops and post them. I'm not sure the wood wedges qualify as "cool" but I suppose they still belong in the gallery.

Yes we use the special Doppelmayr tool and ram to unload the torsion springs. They are in fine shape.

[liftmech]

LiftTech, on Mar 11 2009, 09:02 AM, said:

It doesn’t, it’s more like spring force testing.

Yeah, that would be more accurate, wouldn't it? Never really thought of it that way.