automatic prusik fo...
 

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[Closed] automatic prusik for rope work at height. what are they called?

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What is the device name that is used in working at height?

They are metal have a handle to easily slide up and down the main safety rope. Easier than a prusik. Not for ascending but more fall arrest if working on a rooftop.

Can't describe very well but hopefully someone understands.


 
Posted : 21/11/2017 2:29 pm
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petzl grigri will do that I seem to remember.


 
Posted : 21/11/2017 2:32 pm
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Have a look at the petzl website https://www.petzl.com/GB/en to see if you recognise what you are after


 
Posted : 21/11/2017 2:38 pm
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I can think of two devices. One is the [url= https://www.petzl.com/US/en/Sport/Belay-devices--descenders/GRIGRI-PLUS ]GriGri[/url] which is a belaying device for climbers but auto-locks if the handle is released. The other is also a Petzl device, the [url= https://www.petzl.com/US/en/Sport/Belay-devices--descenders/STOP ]Stop[/url] which is generally used by cavers. Again it has an auto-lock mechanism.


 
Posted : 21/11/2017 2:39 pm
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I thought giri grill was more for ascending? Thing I am thinking of is more used with a body harness.

Let me try to find apicture.


 
Posted : 21/11/2017 2:43 pm
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Petzl Shunt

https://www.google.co.uk/search?q=petzl+SHUNT&rlz=1C1GGRV_en&source=lnms&tbm=isch&sa=X&ved=0ahUKEwidmY6M88_XAhUI1hoKHWcyCqsQ_AUIDCgD&biw=1703&bih=793

A Grigri is a belay device and is not an auto lock device, as you must keep your hand on the dead end of the rope for it to work properly.


 
Posted : 21/11/2017 2:43 pm
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[img] [/img]

Similar to this.


 
Posted : 21/11/2017 2:46 pm
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Sounds like your either talking about a shunt or at a push an [url= http://www.petzl.com/US/en/Sport/Ascenders/CROLL ]ascender[/url]. Neither are great for fall arrest as much more than a slump onto the rope risks damaging the sheath of the rope.


 
Posted : 21/11/2017 2:48 pm
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Don't know what that is in the photo, but the petzl ASAP is their mobile fall arrest system. https://www.petzl.com/GB/en/Professional/Mobile-fall-arresters/ASAP


 
Posted : 21/11/2017 2:52 pm
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sounds a bit like a [url= https://www.petzl.com/US/en/Sport/Ascenders/ASCENSION ]jumar[/url] to me, although I don't know that i'd use it as fall arrest. Possibly could prevent a fall?
GriGri is a belay device isn't it? (edit - yes, like you've already covered)


 
Posted : 21/11/2017 2:54 pm
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I may be using incorrect terminology. Fall prevention rather than fall arrest sounds more accurate.


 
Posted : 21/11/2017 2:56 pm
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We used to (mis)use a Shunt for self top-roping. It requires the rope to be under tension otherwise it doesn't move so had to hang a rucksack off it. Obviously in the situation we were using it we needed it to move upward rather than act as a safety hand. It also needs to be aligned with the line of the rope so couldn't be used in the manner shown in the above shot.


 
Posted : 21/11/2017 2:56 pm
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Agree with a shunt - not for a dynamic fall though.

EDIT - whitestone is right though. Perhaps you need a Stop. You need to pull the handle to allow the rope through. Seems a bit OTT though.


 
Posted : 21/11/2017 2:57 pm
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If you're thinking of things like this https://www.petzl.com/US/en/Sport/Ascenders

then you cannot use them for fall arrest, only ascending - they have teeth on the inside of a cam that will shred a rope (even a static one). For anything dynamic or for tensioning then you need something with a smooth surface like a shunt or grigri as mentioned above.


 
Posted : 21/11/2017 2:58 pm
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Makes sense thanks. Given me some more information to work with.


 
Posted : 21/11/2017 3:19 pm
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In the situation you're describing, a Grigri would be a good choice. I've used one for exactly the same kind of work as shown in the pic above. Slides up the rope easily, slides down it with care, but autolocks if yanked. Petzl do a version without the release handle and with an integral rope as an adjustable work positioning lanyard called the Grillon

https://www.petzl.com/GB/en/Professional/Lanyards-and-energy-absorbers/GRILLON ]

As others have said ascenders/jumars are not the right tool, as if they're shockloaded there's potential to tear the rope sheath. Shunt will work, but it's a bit old school now.


 
Posted : 21/11/2017 3:28 pm
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DMM Anthrone(sp?) Range has some stops and double stops iirc. They also do the minimal Buddy as well

Edelrid have a product called the Wind Up too...(!)


 
Posted : 21/11/2017 3:39 pm
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Good idea to knot the rope down from whatever device you are using, stops you falling off the end in case the device you are using slips. If doing what your picture shows I would use a Grigri as that's what I own and am familiar with. There will be devices more suited to what you want.


 
Posted : 21/11/2017 3:56 pm
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You said it has a handle.... Petzl I'D?

[img] [/img]


 
Posted : 21/11/2017 3:59 pm
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A work positioning device/lanyard or designed to prevent a fall, usually any slick is kept at a minimum as not intended for a shock load... Things like the grillion adjustable lanyard or a shunt mechanical prussic) etc.
A fall arrest device is intended to stop a fall once it has occured, usually dragged along via a lanyard or a shock absorber... Petzl ASAP etc.

A gri gri is neither, it is a belay device for climbing rather than a work positioning/fall arrest device. But if it's for home use it can be useful.
The photo shows the use of a rope clamp as a work positioning device, there is no slack in the system, so if he trips/slips he won't fall.

Ascenders are great for moving up a rope, but snag moving down.

If I'm working at the top of a crag I tend to use a Petzl connect adjust (adjustable lanyard) clipped to decent protection and shorten/lengthen the lanyard when needed... Still need to avoid shock loading it.

Really depends whether it's for work or personal.


 
Posted : 21/11/2017 4:06 pm
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Sorry to rant on. One point is the gri gri is an assisted braking device, you still need a hand on the brake rope. The Petzl ID or Rig (industrial beefed up Gri Gri) have rest position s for the handle which do not require you to keep hold of the rope.... Although they are twice as expensive as the gri gri


 
Posted : 21/11/2017 4:14 pm
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Nope, both ID & RIG require control of the tail. It’s in the user manual. Especially the RIG as the smaller van has a narrow sweet spot fit descending on.
For fall arrest use on a rooftop it depends on what is in place. If there is a mansafe system it will have a soecific traveller & will need to be used with a specific lanyard.
If you’re intending to rig a line & use a device on it I’d personally be using my ASAP Lock on an Asapsorber. Travels freely so is fairly hands free (although Little is when used horizontally.
A Shunt or similar rope grab needs moving manually and there is a risk of ‘towing’ it if you fall whilst holding it/its lanyard (which should be super short).
Rather than a Gri Gri you may be thinking of a Grillon which looks very similar but comes with its own line and is subtly different to the Gri Gri in that it is spring to the locked position whereas the Gri Gri requires a load to lock.
Assume this isn’t a professional enquiry as then you’d go to a WAH specialist, if you don’t know what you’re doing you could put yourself in a very dangerous position...


 
Posted : 21/11/2017 4:49 pm
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If the handle is in the working position (same position as a gri gri) then yes you need to maintain control of the brake rope with you hand. On the ID and Rig you can push the handle into the rest or store position where you do not need to keep hold of the rope. The ID in chrisdws photo has its handle in the store position. If it was pointing up it would be in working position, somewhere in between is rest position.

[img] [/img]


 
Posted : 21/11/2017 4:56 pm
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+1 Petzl Stop (aka 'Plummet' - squeeze the handle to go faster 😈 )

[img] [/img]


 
Posted : 21/11/2017 4:57 pm
 Yak
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Ah, the mighty petzl stop. I had one, but it was more 'slow' or 'plummet' . No 'stop' about it at all 🙂 .
Might have been time to retire it, maybe.


 
Posted : 21/11/2017 5:14 pm
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Misunderstood you regarding ID/RIG & control hand. Although you should never push either handle to ‘store’ when rigged as it can damage core of rope.
Only ever used a Stop a couple of times in 6 years to rig a tight line tbh, I’m an ID baby, although the new 2018 RIG looks quite nice with its stainless wear plate.


 
Posted : 21/11/2017 5:23 pm
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All good info.things like a back up knots etc I had considered and used before but other good points and info on the devices too.

The use is manly roof work only DIY now but have done it for money. I have run prusik type setups before but they can be a pita so was looking at other solutions for some work on a building I am interested in. I always do a lot of playing and testing on the ground and am very slow and methodical when at height. Never had a near miss and want to keep it like that.


 
Posted : 21/11/2017 5:24 pm
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I thought the Petzl mechanical prusik was the Zigzag?

No idea if it's what you really need on your roof though 😉


 
Posted : 21/11/2017 6:00 pm
 grey
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TheBrick if it's just for DIY use I can send you a never used but out of date one of those stops that's in your picture.
Email in profile.


 
Posted : 21/11/2017 6:04 pm
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Jesus f***...
So much incorrect, confused and downright dangerous information posted above its unreal...
Mattbee is bang on (as he should be - he's my Ops Manager)
What the OP is describing is the "Stick Run" or to give it its correct name - Rope Grab
[img] https://www.partnerconnect.honeywell.com/~/media/EssPortal/Product/Images/PPE/Fall-Protection/Rope-and-Cable-Fall-Arresters/STICK-RUN/STICK-RUN.ashx?h=278&la=en&w=200&hash=5D1FA8DA71D28BEC29F480DD72496D50E5099CD3 [/img]


 
Posted : 21/11/2017 11:36 pm

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