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How are clamp-less fixed grip chair attached to cable?

Riblet grip clip NDT

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#1 MarkV

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Posted 19 March 2016 - 05:25 AM

I have noticed that on some ski lifts with non-detachable chairs there is no visible clamp. I assume there is some sort of pin screwed into the cable and the chair is hung over this pin. Is this correct? How does the ski area inspect this for integrity? Does mounting point get moved periodically?

#2 Kelly

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Posted 19 March 2016 - 08:20 AM

Good questions Mark...
The basic clamp term is referred by the ski industry as a grip. From that component there are two subsets – an external** grip and a internal grip. The internal grip (referred by the industry as a “clip”) was used primarily by the Riblet Tramway Company***.
Attached File  Superior-clip.jpg (97.45K)
Number of downloads: 111
The clip has a number of advantages such as a smoother ride, has no moving parts and is inexpensive to manufacturer - this shows the cable going "under" the sheaves.
Attached File  Riblet-holddown.jpg (194.8K)
Number of downloads: 183
The clip is “woven” into the cable (called a haul rope by the industry), this picture shows the machine that pulls a short section of haulrope together into a “birdcage” this then allows the clip to be inserted between the “strands” of the haulrope.
Attached File  detensioner.jpg (105.05K)
Number of downloads: 163
Riblet closed shop in 2003 but their webpage is still available: http://www.riblet.com/index.html
The same style of clip with many strength upgrades is still available via Superior Tramway.
Scroll to “clips” for a full picture set: http://www.superiort.../downloads.html

**External grips have two subsets – fixed and detachable…the more common marketing term for a chairlift with detachable grips is called an express lift. More information and technical terms can be found here.
http://www.skilifts....ld/glossary.htm

***The company name comes from the founder Byron Riblet who got his start building ore hauling ropeways. The clip idea was used well before Byron’s time but much of his sale literature includes the term “clip”. The name stuck.

When you’re riding a Riblet the history goes back to the 1930s…it could be called America’s first true chairlift manufacturer. Riblet also manufactured America’s first detachable chairlift. Riblet built around 170 ore tramways and over 400 chairlifts.

Early chairlift history: http://www.theskijou...Tramway-Company
Complete History of Byron Riblet …Tramway Titan: http://www.amazon.co...s=tramway+titan

Clip moving schedule topic can be found here: http://www.skilifts....?showtopic=4616
www.ropetech.org

#3 Sacdelic_Skier

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Posted 19 March 2016 - 09:42 AM

what was the first detach riblet chair?
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#4 kwoodsparky

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Posted 19 March 2016 - 10:41 AM

Not on purpose

#5 MarkV

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Posted 25 March 2016 - 03:59 AM

Thanks for detailed explanation, Kelly. And link to inspection and moving details. Still is un-nerving to ride chair with no visible means of support.

#6 liftmech

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Posted 26 March 2016 - 07:08 PM

Pretty simple and effective system. I worked on those for a few years and grew to like them. The clip can be unintentionally removed, yes, but not when the lift is properly operated.
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#7 Kelly

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Posted 27 March 2016 - 04:24 AM

Kwoodsparky is making a reference to the only disadvantage of the Riblet clip…improperly installed clip, tower swing guard misadjustment, wrong profiled loading ramp causing swing are issues that can result in the clip “detaching” from the haulrope.

As liftmech (a former Riblet specialist) states in the above post those issues are primarily maintenance related and not an issue with the design of the clip.

Sacdelic…Exploring Riblet’s early chairlifts, it actually makes sense that Byron produced a detachable chairlift as this was a common feature for ore tramways. Mt. Spokane Washington had a Riblet double seat detachable – Spokane was also the town that Riblet was based in (still is).
Out There Monthly has a history reference of this chairlift with a nice picture of that detachable.
http://www.outtherem...i-lift-origins/
Spokane=Spoke-kann

MarkV…on strength issues, take another peek at the machines used to “open” the cable, notice the large hydraulic rams that are needed to overcome the clamping force of the rope. The clip strength is derived from the type of steel used, the size may seem small but the average car has a smaller size (relatively speaking) axle spindle.
Attached File  spindle-comparo.jpg (98.92K)
Number of downloads: 50

It’s worth noting that the nickel alloyed steel (a close relative of stainless steel) used for this clip makes it very strong.
Link gives more info on nickel steel use and strength.
https://www.nickelin...boutNickel.aspx

More tramway history, Riblet built one of the longest ore ropeways at 26 miles with 280 towers in Nepal. Pictures with story of the son of the site engineer: http://historylesson...evelopment.html
www.ropetech.org





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