alpinforum.com

I have been involved for many years with aerial ropeways in Australia.
I am currently working as a Health & Safety Consultant in Victoria Australia where some time ago there was a chair slippage which I am convinced resulted from a grip having been loosened by an unknown person (either sabotage or simple vandalism, neither of which would be for the first time in this country). There is evidence from more than one reliable eye witness that someone was seen tampering with the grip on the night before the incident. That matter is background only and is not the main subject of my e mail to you - that issue will resolve itself by the legal processes currently underway.

That aside, the present Statutory Authority is taking the view that because the grips on this lift are bolted grips, they are therefore inherently unsafe and must be replaced with spring loaded grips. This lift is about 50 years old, is a very slow sightseeing 2 seater lift and can't be simply modified to accommodate commercial spring loaded grips. In the view of our Statutory Authority, spring loaded grips are inherently safe and do not slip, whilst bolted grips are inherently unsafe and even when correctly maintained, are likely to slip as a result of rope diameter changes due to temperature and stretch during service. (In my view, both of these propositions are doubtful)

I have had many years experience inspecting aerial ropeways both for the Statutory Authorities and since retiring from their employment.
My experience tells me that whilst there are some good arguments in favour of spring loaded grips, they nevertheless migrate along the haul rope and do slip under some circumstances. To my knowledge, there have been several examples in the last few years of these grips slipping at various locations around the world.

I also know that it is often impossible to simply replace one type of grip on a chairlift with another because often the design of the lift requires extensive modifications to accommodate the new design of grip and that sometimes the economics don't add up. My experience also tells me that properly maintained bolted grips are not inherently unsafe.

I am hoping the knowledgeable people who are members or associates of your authoritative website will be able to give me some answers to the following questions:

* are you aware of any place in the world that has specifically banned bolted chairlift grips by law and if so where, when and why ?
* can you refer me to any authoritative source of information which shows clearly that chairlifts with bolted grips are still permitted to operate ?
* can you refer me to any authoritative source of information about incidents in which spring loaded grips have slipped and caused accidents ?

In terms of aerial ropeways, we in Australia have nowhere near the broad experience that is available in Europe and America.
I would really appreciate any help I can get on this please.

14, Die Verbindung des Zugseiles mit dem Laufwerk ist seilschonend auszuführen.
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Bei Verwendung von gefederten Klemmen bei Förderseilen und durchgehenden Zugseilen muss im ungünstigsten Lastfall und einer betrieblich möglichen Verminderung des Seildurchmessers um 10 % eine mindestens 3-fache Sicherheit gegen Rutschen vorhanden sein. Eine minimale Wegreserve von 1 mm gegen innere Blockierung der Klemme ist in diesem Fall nachzuweisen. Bei durchgehendem Zugseil müssen die Ein- und Auslaufradien der Klemmen mindestens dem 5-fachen Seilnenndurchmesser entsprechen.
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8. Förderseilklemmen sind so auszubilden, dass sie das Seil ausreichend umfassen und beim Drallausgleich sich nicht vom Seil lösen können. Sie sind seilschonend zu gestalten und müssen leicht versetzbar sein.
9. Die Abziehkraft der Förderseilklemme muss mindestens doppelt so gross sein wie die grösste Zugwirkung der Schleppvorrichtung in Seilachse. Als Reibwert ist 0.16 anzunehmen.
10. Die Klemmkraft der Förderseilklemme muss bei Verringerung des Seildurchmessers um 15 % noch aufgebracht werden können.
11. Bei Verwendung von Förderseilklemmen mit Federspeicher darf zur Erzielung der Klemmkraft der Federweg zu höchstens 80 % ausgenützt werden.

mit denen er als Sicherheitskonsultant dem Liftbetreiber die Umrüstung "schmackhaft" machen möchte

My experience also tells me that properly maintained bolted grips are not inherently unsafe.

Pilatus hat geschrieben:Er schliesst damit ab, dass ihm seine Erfahrung sage, dass gut gewartete Federklemmen nicht unsicher seien.

My experience also tells me that properly maintained bolted grips are not inherently unsafe.

seilbahner hat geschrieben:Aber: Auch eine Federspeicherklemme wird festgeschraubt.