removeable/adjustable false crotch
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SteveBullman
User Formerly known as stephenbullman
it'll work.....but are you hoping to retrieve it from the ground? cant see how with the big krab if so?
also why such a big pulley?
also why such a big pulley?
big pulley
my other smaller pulley got stolen. large krab is 4 knot 2 go through but can use a smaller one. this is just a quick display most my tools are at work. im home with stomach virus. yes this setup is made 2 b removed from ground well a soft groundstephenbullman said:
SteveBullman
User Formerly known as stephenbullman
doh....i was looking at it in reverse
ok looks good then, just the pulley. a petzl fixe would be more suitable
ok looks good then, just the pulley. a petzl fixe would be more suitable
Jim1NZ
ArboristSite Guru
I defiantly wouldn't pull that or any other system with a pulley out of the top of the tree unless it is specifically made to take a thrashing.
Bring it down with an access line or throwline
Bring it down with an access line or throwline
no way i would use a small pulley like the FIXE, think of the sharp bend the rope takes over the pulley with your weight on it. Go Big! and lower it like a cambium saver form the ground, using your throwline to slowly lower it....
this is what i use:
^ ignore the non locking biners, i needed my lockers for something else at the time)
shown with treeclimber :biggrinbounce2: on rope)
i quickly rigged it up to demonstrate, when in use i use 1/2" arborplex for the climbing rope. but you get the idea. The black thing is a canvas/vinyl edge guard, works nicely for protecting tree limbs when floating false crotch is hauled up.
to set it up:
i throw my throwline/weight over the limb i want, tie it to the end of the 11mm static line and pull it up (with my 1/2" climbing line already thread thru the pulley). I then anchor it down at ground using a tensionless hitch around a neighbouring tree.
to pull it down: i untie the static anchor line, attach my throwline to the end and pull the climbing rope , pulley down , using the throwline to SLOWLY lower the entire works.
^ ignore the non locking biners, i needed my lockers for something else at the time)
shown with treeclimber :biggrinbounce2: on rope)
i quickly rigged it up to demonstrate, when in use i use 1/2" arborplex for the climbing rope. but you get the idea. The black thing is a canvas/vinyl edge guard, works nicely for protecting tree limbs when floating false crotch is hauled up.
to set it up:
i throw my throwline/weight over the limb i want, tie it to the end of the 11mm static line and pull it up (with my 1/2" climbing line already thread thru the pulley). I then anchor it down at ground using a tensionless hitch around a neighbouring tree.
to pull it down: i untie the static anchor line, attach my throwline to the end and pull the climbing rope , pulley down , using the throwline to SLOWLY lower the entire works.
Jim1NZ
ArboristSite Guru
SRT-Tech said:
Are you for real?! Do you rope into a carabiner, what about the bend in the rope then? I know in this situation there would only half the loading too.
If the pulley is rated to at least 22kn i would most defiantly climb on it as my anchor point but there is no way i would pull it out and let it crash to the ground.
I dunno, i just dont trust those lil pulleys (FIXE etc) for an anchor point... ....... the little rivet holding them together does NOT inspire confidence in me.
I have found that a rope bending over a small pulley seems to flatten more than a rope bending over a large pulley (like the one i showed). (besides, my big pulley has a sealed ball bearing in it! very smoooth)
just me...your milage might vary.
I have found that a rope bending over a small pulley seems to flatten more than a rope bending over a large pulley (like the one i showed). (besides, my big pulley has a sealed ball bearing in it! very smoooth)
just me...your milage might vary.
Jim1NZ
ArboristSite Guru
Ball baring pulleys are very nice.
Everyone to their own, bigger is better i suppose - 5x diameter of rope is perfect.
Everyone to their own, bigger is better i suppose - 5x diameter of rope is perfect.
JohN Dee
ArboristSite Operative
(WLL), Are you trying to say you get that in the tree from the ground or do you rig that when you're up the top?
Cuz getting that into the tree from the ground looks mighty difficult.
Anyways please explain
Cuz getting that into the tree from the ground looks mighty difficult.
Anyways please explain
Climb020
ArboristSite Operative
Couldn 't imagine try to either set or retrieve that set-up from the ground. That would definitly have to be lowered due to the beating it would put on that pulley. Seems too much of a PITA to me. Try to keep it plain and simple with parts that could take the beating of a 100' fall. My buckingham one works just fine but getting a new rope guide tomorrow similar to what you have ther but with the small pulley from Sherrill.
Jim1NZ
ArboristSite Guru
Yea im with 020, but i use a rope guide and bring it down with my access line most of the time.
only when up a tree
this is only practical in some situations!! can only be set up while in the tree and only removed over soft ground. this is just a display mod only!! the one i use is made with double braid and steel krabs with a much lighter (alum) pulley.JohN Dee said:
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There is nothing wrong with climbing on a small pulley.
If you look at the size of the pulley on the ART Rope Guide its size is about the same as a micropulleys.
If you look at the size of the pulley on the ART Rope Guide its size is about the same as a micropulleys.
Given same axle/sheave friction a larger pulley will give more leverage over the friction, and so thereby be more efficient; and bend line less; and given the same amount of rope running thru each pulley; a larger pulley will make less revolutions: have a longer life/ less wear. Similarly a larger wheelbarrel wheel on same axle will be more efficient (but s-lightly harder to start rolling); and last longer on tire tread and axle/bearings due to the distance modifier.
If lowering a load thru pulley; with the load on 1 end and control totally separate on the other end; the force must crank thru pulley; so pulley diameter bending line makes a bigger difference in how line is leveraged. In my imagery, a load position on 1 end of line thru pulley, that the control on equal/opposite end that also connects back to load (as in tree climber's DdRT); so that load(climber) belays/controls self; pulley size makes less difference on the leveraging of the line(but not on the efficiency of the pulley). i see this because in this setup; the force transfer can be across the air to the other leg of line support (dead ending at saddle); not so much thru pulley/support; especially as that positicon becomes more frictional. This small factor is why a 100# man should not descend on a friction hitch in SRT, but a 300#man can descend on same in DdRT(even though the tree climber has 2/1 over self, on self lift in DdRT).
But, ye are write to say, that the axle on a small pulley is small; especially pulled by your weight forces perpendicular to the spread supports of the cheek plates support on the axle.
i think that 8/1 is about perfect/ no leverage strength loss example we see for supple braids, 10/1 on 3 strand, but this is all relative to line's resistance to bending(because the resistance to bend is leveraging). Thus steel cable requires more (and specially shaped sheave to support the 'loaded belly' of the cable). Kevlar etc. can easily get up to 30x (which cable exceeds) and also needs specially shaped/grooved sheaves. Leveraging by bend in Standing part is different than by bight), not a strength loss, but load force increase; to leave less useable range of rope tensile rating remaining. The rope leveraging around the bight of a small turn/pulley is an actual strength loss, by compressing fibers on inside of bight. The compressed / push fibers don't support the load activity in this tension only device/rope, so only the outer arched fibers are tensioned/ helping to carry the load. Thereby, to leave less useable range of rope tensile rating remaining; just by different means.
If lowering a load thru pulley; with the load on 1 end and control totally separate on the other end; the force must crank thru pulley; so pulley diameter bending line makes a bigger difference in how line is leveraged. In my imagery, a load position on 1 end of line thru pulley, that the control on equal/opposite end that also connects back to load (as in tree climber's DdRT); so that load(climber) belays/controls self; pulley size makes less difference on the leveraging of the line(but not on the efficiency of the pulley). i see this because in this setup; the force transfer can be across the air to the other leg of line support (dead ending at saddle); not so much thru pulley/support; especially as that positicon becomes more frictional. This small factor is why a 100# man should not descend on a friction hitch in SRT, but a 300#man can descend on same in DdRT(even though the tree climber has 2/1 over self, on self lift in DdRT).
But, ye are write to say, that the axle on a small pulley is small; especially pulled by your weight forces perpendicular to the spread supports of the cheek plates support on the axle.
i think that 8/1 is about perfect/ no leverage strength loss example we see for supple braids, 10/1 on 3 strand, but this is all relative to line's resistance to bending(because the resistance to bend is leveraging). Thus steel cable requires more (and specially shaped sheave to support the 'loaded belly' of the cable). Kevlar etc. can easily get up to 30x (which cable exceeds) and also needs specially shaped/grooved sheaves. Leveraging by bend in Standing part is different than by bight), not a strength loss, but load force increase; to leave less useable range of rope tensile rating remaining. The rope leveraging around the bight of a small turn/pulley is an actual strength loss, by compressing fibers on inside of bight. The compressed / push fibers don't support the load activity in this tension only device/rope, so only the outer arched fibers are tensioned/ helping to carry the load. Thereby, to leave less useable range of rope tensile rating remaining; just by different means.
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climbing on a micropulley might be perfectly safe, but i just get the absolute heeby jeebies doing it, cuz of that lil aluminum rivet holding the pulley. I'm sure its fine, but nothing will convince me to use a micropulley, except for my lanyard adjust. (even then i'm still tied in with the rope overhead)
I like my big fat 1/2" stainless steel axle on my Petzl.! bombproof
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this is not 4 climbing
i love my rope gide and use mostly 4 tying in on a crotchless smooth spar.normaly i dont use as a friction saver unless im doing lots of pruning and need 2 save energy. i think the rope guide is very important tool 4 me because i rarely ever rely on crotches and seldom/never leave stubs.
stubs are ugly and they cause hang ups. they also do more property damage than necessary and dont lay nice on a truck/ground or any where 4 that matter
very similar 2 rope guide but is designed 4 lowering limbs and wood. i got the idea from the rope guide.rahtreelimbs said:
i love my rope gide and use mostly 4 tying in on a crotchless smooth spar.normaly i dont use as a friction saver unless im doing lots of pruning and need 2 save energy. i think the rope guide is very important tool 4 me because i rarely ever rely on crotches and seldom/never leave stubs.
stubs are ugly and they cause hang ups. they also do more property damage than necessary and dont lay nice on a truck/ground or any where 4 that matter
