New (possibly) knee ascender

Jehinten

Well-Known Member
OK, this all got started as I was reading about the SAKA being taken off the market, and to my understanding it is because of a "bungee in a straw" (just so anyone who reads that opening line and groans thinking this is going to be ranting about that situation, please continue reading, that is not what this is about) it got me thinking about how to get a knee ascender to advance up the line without a bungee at all. There are some ideas on how to make that happen with springs and retractable lanyards, and that may work great and will certainly be compact, I chose to find a way that is easy for anyone to build. Due to the simplicity of this design and the fact that I am simply putting other people's products together and not really "creating" anything, I do not think this would be marketable. The design is so simple that anyone who wanted one would simply rip it off and build their own, which is exactly what I want them to do. If you do think this has any potential and decide to try it, please post pics of what you have come up with for others to try as well. All of that being said I have just made my own version of this, and have done very limited testing (basically I went up a rope twice). If this were anything life support I would not put it out there so quickly, but since the worse that would happen if it fails is that you have to advance your ascender by hand, I think it is OK to let others try it out. Not only that, but I do not climb every day so you would have to wait a long time for me to test it out thoroughly . Please don't do anything reckless like trying to ascend on this without a climbing device as well, the decent will not be pleasant, and just so it is in writing use at your own risk (however small of a risk that would be)

One last comment before I begin explaining how to set it up, I have not seen it set up like this before, I have seen several knee ascenders strapped to thighs, raised by hand, raised by bungee... this one is advances on its own without any bungees or springs. If this has been done before, please let me know so that credit goes where it is deserved, and this will just be me rediscovering it and putting it online for others.


Building the ascender.
So just like all models before you still need an ascender, preferably a chest ascender but really any ascender should work. I used this one https://www.ebay.com/itm/Epic-Peak-...zsAAOSwbsBXj-yQ:sc:USPSFirstClass!47715!US!-1 Now I know buying climbing gear on Ebay may not be the best thing, but it fit my needs for this application as I did not own a chest ascender previously. Make a foot loop attached to your ascender so that when wearing it the ascender is at about knee level. You can use any material you want rope, webbing... just as long as it is strong enough for you to stand on as this will be the only part of the system that is load bearing. Next you will need a longer cordage approximately 5-6 feet long (length may vary depending on your height and harness set up) and either tie or splice an eye into one end for a connector of your choice. I used a 3/8" hollow 12 strand that I received 100s of feet of in a bag of rope, just because it is strong enough, easy to splice, and I needed to use some of it up. These are the connectors that I used https://www.homedepot.com/p/Everbil...el-Plated-Swivel-Trigger-Snap-44164/205874120 You can use any connectors that you want, but I liked these for the ease of clipping/unclipping and I like the swivel for proper orientation. You will need two of these clips on this length, one on the end (previously mentioned) and one will have the cordage run through the eye of the trigger snap. The last step is to determine the final length of that cordage with the connectors and tie it to the top of the knee ascender, a splice could be used here as well once you know for sure the length that you want.

Sizing the correct length .
To set the correct length set an SRT access line and prepare for an ascent. Take up enough slack in your climbing system so that your feet are barely touching the ground and clip the fixed connector to your foot ascender. The running snap will be attached to your bridge connector (Rook, ring what ever you use) place the foot loop/ knee ascender on your other foot and tie the two halves together. To get this to work the length will need to be adjusted with one foot down and the other stepping up. Without a bungee or spring in the system you cannot put both feet down at once. When hanging from a rope this does not create a problem, if you try to set all of this up without using the ascent line it may test your balance. 20180228_211811.png
The above photo is borrowed and cheaply edited to show the setup. The red lines are your cordage and the blue is the chest ascender


To use this system.
Simply begin your ascent up the rope with only your foot ascender until you have enough rope weight below you that it will self feed. Step into the foot loop, clip the two trigger snaps and proceed to climb. Each time you stand up on one ascender, this setup will raise the opposite ascender for the next step.


I cannot seem to get pics to load from my phone onto the desktop that I am using now, so I will go through and edit once this is posted from my phone so that you can see what I am trying to put into words. Once again any other ideas and improvements are welcome. And I do not have any pics during "the build" as it was just a prototype that happened to work on the first try. It should be easy enough to figure out from the above post and pictures.

A couple of things that I have already thought of, if it were desired you could do away with the terminated connector and make a second foot loop for the foot ascender leg, or clips at the bottom on both sides if you have a boot with foot loops built in.

20180228_165807.jpg
 
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Jehinten

Well-Known Member
It also rolls up and stores almost as compact as the ascender itself. There are smaller options out there for ascender to make it more compact. 20180228_164841.jpg



Edit: one thing I did forget to include was that if you choose to use an ascender, either the knee ascender or the foot ascender that is possible to kick out of, I would put some sort of breakable link in the system. Either a magnet connection, a spring, or a bungee so that it is more forgiving to you when you step down and the force is not transferred to your climbing rope.
 
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FreeFallin

Well-Known Member
I was chewing on knee ascenders this morning and had almost the same epiphany.

To make the left ascender go up, you just need to tie it to the right ascender that is going down, and pass it through a redirect.

This could be as simple as a piece of Para cord. I do think a little bungee can improve it by letting you put both feet on the ground, but it'seems non essential.

Great idea and diagram @Jehinten ! I am going to try to make a short video today and try it from a hook.
 

Jehinten

Well-Known Member
I was chewing on knee ascenders this morning and had almost the same epiphany.

To make the left ascender go up, you just need to tie it to the right ascender that is going down, and pass it through a redirect.

This could be as simple as a piece of Para cord. I do think a little bungee can improve it by letting you put both feet on the ground, but it'seems non essential.

Great idea and diagram @Jehinten ! I am going to try to make a short video today and try it from a hook.
Para cord, for the non load bearing was my first thought but I decided on the 12 strand simply because I have so much of it. Although the Para cord would make it even more compact for when it is not in use. The only concern I can think of with bungee, is that you will actually lose lift on the ascender. With a non stretching cordage it raises your foot up as you climb, instead of waiting for your foot to rise so that it can advance. Possibly making it a faster ascent for anyone who is competing. Not sure if a home made knee ascender would be allowed in competition anyways?
 

FreeFallin

Well-Known Member
I thought about that and I wonder if a much stronger bungee, like a tie down would let you put your foot down but not respond to normal climbing tension.

Just thoughts
 

FreeFallin

Well-Known Member
One big difference I see between this system and the Gibbs, HAAS, SAKA is that each of those systems add resistance to each left step because you have to stretch out the bungee and store potential energy to pull the left ascender up when you lift that left foot.
That's the same as putting a 5-10 lb rock on your belt for every left step.
This system could cause less resistance because it only creates enough drag to lift the left ascender (maybe .5lb), and it moves that lessened load to the right leg.

Interesting.
 

Jehinten

Well-Known Member
That is very similar, minus the bungee. It is not surprising that someone has done something like this before, as it is a simple setup. Thanks for finding that, you seem to have a reference for just about everything discussed on here. I know I have studied a few of your hitch drawings in the past when trying to tweak a system. I appreciate the info here and in other post. Thanks again

As for the working in unison, it is very natural (at least after using a rope walker setup) for the required action to make this work. I've had a SAKA since they were still being sold at treestuff, so its possible that it is a little more intuitive for me to pick up that sequence than maybe someone who is trying it out for the first time.

Your system is basically a double bungee rope walker, without the bungee. Like with the frog system were you have to use a hand and foot working in unison, you have to coordinate both feet to work in unison.
View attachment 49925
A pulley at the bridge snap might help.
 

Bob Bob

Well-Known Member
Thanks Jehinten for the idea and concept. Ordered the cheap chest ascender and will be looking for a small pulley for the bridge connection...If it works for me I'll include it in one of the videos.

Is there a chance the set-up will fight the tending action of the H.U.T. for the SRT device being used?
 
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misfit

Active Member
It's a clever idea, and I like your thinking "outside the bungee," but I don't think I would like it. I have not tried it, and I have trouble visualizing how it would work in actual use, so I reserve the right to change my mind. It seems too complicated to me. It appears to create a relationship between the feet when I would prefer to keep them as independent as possible. I would want the knee ascender to go up when that knee goes up, not when the other foot goes down. I would also prefer to have something that is easier to disconnect and not need to be stowed once aloft.

What I am using is a homemade knee ascender that I simply strap to my leg under my knee and connect to a foot loop. It's just like a foot ascender with the ascender mounted very high. I attached an ascender ( https://www.treestuff.com/store/catalog.asp?category_id=232&item=3576 ) to the top part of a Notch Handsaw Leg Mount ( https://www.treestuff.com/store/catalog.asp?category_id=221&item=16793 ). I drilled two very small holes in the mount so that I could attach the ascender to it with ordinary zip ties. I then attached a common web lashing strap ( https://www.amazon.com/gp/product/B004PL4H0O/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1 ) to the ascender and cut it to length. I put an XSRE carabiner on the end for quick attachment to my foot loop ( https://www.treestuff.com/store/catalog.asp?item=15983 ), but you could also just run the strap through the foot loop and back up to the strap buckle. You could also do without the foot loop and run the strap under your foot and back up to the buckle on the strap. If you want to loan it to someone with longer or shorter legs, it can be easily adjusted to fit them.

This solution suits me very well. The ascender goes up the rope when I raise my leg and is not dependent on a bungee or my other leg. Once aloft, I disconnect the ascender and leave everything attached because it's not in my way. There is nothing to stow. The only downside that I have found occurs when I get in awkward positions and my knee is not well aligned with the direction of the rope. It can stretch the elastic strap around my knee a bit, but it still works just fine, and once I get back into a normal position, it's all back to normal. So, I won't call it the perfect solution, but it's close to it for me. In the end, if it works for you and you like it, then it's a great idea, even if it is a terrible solution for someone else. We're all different, and we're all right.
 

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Jehinten

Well-Known Member
Thanks Jehinten for the idea and concept. Ordered the cheap chest ascender and will be looking for a small pulley for the bridge connection...If it works for me I'll include it in one of the videos.

Is there a chance the set-up will fight the tending action of the H.U.T. for the SRT device being used?
I am currently using a 48" webbing strap as a chest harness, so I am unsure on that. I would think not, but please let us know.
 

Jehinten

Well-Known Member
It seems too complicated to me. It appears to create a relationship between the feet when I would prefer to keep them as independent as possible. I would want the knee ascender to go up when that knee goes up, not when the other foot goes down.
I'll have to take a closer look at yours, but it seems you may have found a good solution as well. As far as the quoted statement, It doesn't necessarily go up when the other foot goes down, but follows you up when you stand on that foot (that is going down) if that makes sense. When you are ascending it is simply one foot after the other when you climb much like the SAKA would do in a ropewalking setup.
 

Jehinten

Well-Known Member
Like this??

Well I'll be, its exactly like that with a few minor changes that don't do enough to make it my own. I figured someone had to have tried a configuration like this before. I think personally I would prefer the cordage to stop at my rope bridge vs going up to my chest and I think I like the lack of bungee as well for all the reasons listed above. That being said I have not tried it how Mark had it set up, so I could be wrong.
 

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