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sky7high
Oct 6, 2007, 4:05 AM
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Registered: Feb 15, 2006
Posts: 478
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hmmm, seems like a weird combination of a door hinge, lighter wheel, fire extinguisher/grenade safety pin, and the little knob you turn to hold a vernier caliper in place.
I don't quite get how you control the friction on that, but anyway, I'd like to give it a try. How about you buying it and sending it my way?
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capn_nobeard
Oct 6, 2007, 4:36 AM
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Registered: Dec 6, 2005
Posts: 35
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These are called 'rope grabs', they are used in industrial rappelling for window washing via a botswains chair.
They are basically a cam lobe based ascender that you must manipulate before you descend.
The decent occurs on your hard-line (static kernmantle) via you device of choice (we used racks). And the safety mechanism, 'the rope grab' is placed on three strand poly rope (glorified utility nylon)
I don't recommend them for climbing... its basically the same idea of a prussic, or if you feel the need petzl shunt.
The rap style for industrial/commercial applications is awkward, does not fit well with climbing.
I had one of these break over the summer on me (similar design, not sure of the brand however, it was CSA certified)
(edited because I accidentally hit the reply button)
(This post was edited by capn_nobeard on Oct 6, 2007, 4:39 AM)
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skinner
Oct 6, 2007, 5:48 AM
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Registered: Nov 1, 2004
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I thought it might be something like that, I assume that we are looking at the top in this photo, and by clipping into/weighting the loop, it engages mechanism which grabs the rope? In a way it looks similar to the old Gibbs Ascenders.
19mm rope.. I think I'd let my partner carry that 
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stymingersfink
Oct 7, 2007, 2:24 AM
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Registered: Aug 12, 2003
Posts: 7250
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We use something similar as a backup for "controlled descents" when rapping from towers or other similar structures. As sbaclimber was saying, they're really nothing more than a backup (on a separate static line ~ read PITA) to a Fisk descent device  to satisfy OSHA rules (in the States), which in and of itself, may be a good thing considering that many "Tower Technicians" may not have an exceptionally strong climbing background.
Personally, I'd rather do a "controlled descent" on my 9mm static with a grigri than deal with all that crap, but I suppose industrial needs require industrial solutions.
Don't bother purchasing it (or the Fisk), unless you're trying to start up a vertically oriented service business on the cheap.
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treez
Oct 7, 2007, 2:48 AM
Post #8 of 11
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Registered: Aug 11, 2004
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That device gets attached to a "screamer" lanyard which gets attached to your OSHA approved full body harness. It gets used by roofers a lot as they frequently must ascend and descend the roof. Pretty sure it's for fall protection only.
(This post was edited by treez on Oct 7, 2007, 3:00 AM)
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chossmonkey
Oct 7, 2007, 8:11 PM
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Registered: Feb 1, 2003
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No
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ja1484
Oct 7, 2007, 8:19 PM
Post #11 of 11
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Registered: Aug 11, 2006
Posts: 1935
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Well, it seems to work well 
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