Forums: Climbing Information: Injury Treatment and Prevention: Re: [baja_java] Link Cam Report: Edit Log




mheyman


Jan 5, 2008, 7:37 PM

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Registered: Jul 25, 2002
Posts: 607

Re: [baja_java] Link Cam Report
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I wanted to have better idea of multiplication of force due to different placement flair angles so I would have a better idea of exactly what it was I want to avoid. So here is a graph of the multiplication of force at angles from 0 to 27 degrees for a 14 degree cam angle.



I still donít feel that these points have been made clear:

1) Cams will not pull in small angle flairs due to reduced friction. The angles will increase the outward (normal) force and more than compensate .

2) Increased outward forces will increase the chances of prying a blocks loose or breaking rock features.

3) Increased force due to placement flair is not linear and some place not to far above 20 degrees extremely high forces can be generated arresting a fall, and we should expect cams of any brand to break and placements to fail. I agree with JT that we already avoid these placements but for the wrong reason!

I have found this thread extremely informative. Like healyje and others some here I have avoided buying link cams solely because of the perceived weakness of their jointed cams and their complexity. I even made a statement that I would not buy cams that broke. But OP has responded that they designed the link, verified their expectation in tests and compare them to other cams on the market with favorable results. Unlike other mfgs mentioned, I trust OP. Read MDs response heís a competitor!

At the same time I have learned of a failure mode that may well have caused the LC failure in this case which would have occurred to any other cam in the same type placement. If this was the case, then I will have to categorize this failure exactly like the biner comparisons that have been discussed. I think it would be helpful at this point for someone to estimate the possible flair angles the LST cam may have been placed at. I understand that there were other forces at play here and that it wonít be a definitive answer, but if it was likely that the placement flair exceeded 20 degrees then it should not be unexpected that the cam was broken.


(This post was edited by mheyman on Jan 5, 2008, 9:05 PM)
Attachments: graph.jpg (29.9 KB)



Edit Log:
Post edited by mheyman () on Jan 5, 2008, 7:39 PM
Post edited by mheyman () on Jan 5, 2008, 7:44 PM
Post edited by mheyman () on Jan 5, 2008, 7:49 PM
Post edited by mheyman () on Jan 5, 2008, 7:49 PM
Post edited by mheyman () on Jan 5, 2008, 7:50 PM
Post edited by mheyman () on Jan 5, 2008, 8:58 PM
Post edited by mheyman () on Jan 5, 2008, 9:04 PM: to relable Y axis - Force
Post edited by mheyman () on Jan 5, 2008, 9:05 PM


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