Rope Jack

SingleJack

SingleJack

Participating member
Location
W MD
Below is a link to a short 'rough-cut' vid of an different MA technique for pretensioning a rigging rope. It can attach mid-line and can run virtually any length of rope. Certainly not a new idea but one I've been contemplating for some time and finally put a few spare components together today to test the concept ... seems to work well. The MA is approx. 5+:1 -- no pulleys, no extra rope, min. weight, min. friction, quick, easy on-off, might work well 'topside', too ... we'll see ...

<u>Rope Jack</u>


Just messin' 'round on a Sunday afternoon ... Anyway, kinda like the name, though ... can't imagine why
wink.gif
 
Very Clever!

I wondered how you were going to release the ascender under load. It looks like you walk each of them back out a little...is that right?

I'd use a steel locking biner to anchor the setup. Small pick... :)

Ihave an old pair of CMIs that might have a new use.
 
Great idea..a buddy of mine had explained a steup like that too me awhile ago..at the time I couldn't understand how it would work. Are you using this just to get the stretch and shock out of the load being lowered? How do you feel about using this for pulling a tree instead of a come along?
 
I like the idea but...

How much of a load will you be able to apply to the rope due to the mechanical advantage of the lever, and at what amount of force will the toothed ascender damage the rope?

If you get bored &amp; want to conduct some potentially destructive testing, I'd love to know the amount of force applied to the end of the handle that will cause the rope to be shredded.

-mike
 
Thx, Y'all

[ QUOTE ]
I like your Crocs. ... SZ

[/ QUOTE ]
Them's my Sunday-go-to-meetin' Crocs ... thankyouverymuch ...
grin.gif


[ QUOTE ]
... I wondered how you were going to release the ascender under load. It looks like you walk each of them back out a little...is that right? ...

[/ QUOTE ]
Right ... however, I've been given a much better idea of putting a prusik loop in between the CMI and the 'biner so the load can be released without backing out the cams ... great improvement, IMO!

[ QUOTE ]
... Are you using this just to get the stretch and shock out of the load being lowered? How do you feel about using this for pulling a tree instead of a come along?

[/ QUOTE ]
Yeah, I'm thinking' -- just for light loads! The 'hope' will be to use the "Rope Jack" to remove slack &amp; stretch for lowering and maybe to lift the tips on light limbs without having to break out the big guns.

Cams, even 'untoothed' like a Rescucender and Gibbs, have been shown to shred a rope with high loading. There are much better tools for the heavy work.

[ QUOTE ]
... How much of a load will you be able to apply to the rope due to the mechanical advantage of the lever, ...

[/ QUOTE ]
The short handle gives a leverage of roughly 5:1 ... I figure the max. I can apply with one hand will be a safe limit for the ascender and to keep it from shredding the rope.

One important note about that handle: The handle in the vid is a section of a good quality hickory axe handle ... worked OK. First attempt was with a 1X2 pine board ... it BROKE - went a**-over-teacup ... sorry no vid of that, LOL.
 
What did you make the bar out of? I wonder how much more leverage you could get with a longer bar, different spacing between ascenders, etc. Is there an optimal configuration. Could you use like a croll instead of a hand ascender or is the length of the ascenders critical to the function as well. I could see that as a really useful tool. Awesome job Jack.
 
[ QUOTE ]
What did you make the bar out of? I wonder how much more leverage you could get with a longer bar, different spacing between ascenders, etc. Is there an optimal configuration. Could you use like a croll instead of a hand ascender or is the length of the ascenders critical to the function as well. I could see that as a really useful tool. Awesome job Jack.

[/ QUOTE ]

Here you go Kevin...it was mentioned in the longer post above.
[ QUOTE ]


One important note about that handle: The handle in the vid is a section of a good quality hickory axe handle ... worked OK. First attempt was with a 1X2 pine board ... it BROKE - went a**-over-teacup ... sorry no vid of that, LOL.

[/ QUOTE ]
 
[ QUOTE ]

[ QUOTE ]
... I wondered how you were going to release the ascender under load. It looks like you walk each of them back out a little...is that right? ...

[/ QUOTE ]
Right ... however, I've been given a much better idea of putting a prusik loop in between the CMI and the 'biner so the load can be released without backing out the cams ...


[/ QUOTE ]

Tried a B42 tied in a loop and girthed to the CMI and run through the 'biner - held all the load I was comfortable applying and released well. So there was no need to back the cams out like in the vid. A B53 held well but was too hard to release.
Great improvement!

Notice the steel locking 'biner, Tom -- good point, thx!

6679757215_feea4a986f_z.jpg
 
There are many Load Releasing Hitches that could be used that will untie easily. Most of them are tied in a slipped or opened configuration rather than closed like a Blakes.
 
Jack, great work. If you're thinking of selling it as a force multiplier with those toothed cams though you're asking for trouble. Good luck all the same
 
[ QUOTE ]
There are many Load Releasing Hitches that could be used that will untie easily. Most of them are tied in a slipped or opened configuration rather than closed like a Blakes.

[/ QUOTE ]
Sure ... I considered LRH's but they all needed to be tied and untied every time which seemed too 'fiddly' and slow for my goal. I wanted to click-click-click-tension, cleat porty, release-click-click-click-remove. The main advantage of the BH (in the loop shown) is it stays tied all the time which works &amp; meets the goal -- quick tensioning!
smile.gif
 
[ QUOTE ]
Jack, great work. If you're thinking of selling it as a force multiplier with those toothed cams though you're asking for trouble. Good luck all the same

[/ QUOTE ]

Thanks, Reg ... that means a lot. However, I'm not selling or planning to sell anything ... just looking for some peer review of a solution that might make the work easier. And, I've gotten some really great feed-back.

EDIT: Actually, it was you and your Stein videos that inspired me to try this. I was looking for a poor-man's "Accessory Lever" that could work with a Porty for light loads.
 
Jack, if you don't mind I would like to try and make one with two Bulldog OARS. It would have no teeth at all.
It reminds me of a cable puller called a tirvit (sp).

Love the idea.

Gordon
 
You must log in or register to reply here.

New threads New posts

Kask Stihl NORTHEASTERN Arborists Wesspur TreeStuff.com Teufelberger Westminster X-Rigging Teufelberger
Back
Top Bottom