Thoughts on perpetual climbing wall build

Hi all,
I built a backyard bouldering all this summer and am enjoying the workouts but thinking of taking it to the next level to be able to work more endurance (I am more a Trad climber than boulderer but live 1.5hr from the closest climbing gym).

It will be based on this:

rotor

I have been able to get hold of a large spool that with basic framing will be 9feet tall:

spool

this can be wrapped in 4x8 plywood to create the climbing surface and then set on a basic A-frame kinda like this:

A basic braking system would be built by attaching a paracord with heavy weight on the axle that wraps round as the climbing wall spins, this would want to pull the wall in the opposite direction as the climber and thus slow the rotation.

Anybody tried anything like this or have any ideas?

Should be pretty cheap as I can steal the framing from the bouldering wall and buy the spool for $60.

Links to similar (professional) builds:
vimeo.com/45447882
youtu.be/SNirA3dXvnE

THOUGHTS?

Thanks,
Ben

This is really cool.

But I'd rather climb outside. I'd rather climb 30 feet of crap rock outside than a wheel of plastic holds inside, any time.

But it's still really cool, and definitely awesome for some folks.

But I'm done with plastic. I haven't set foot in a rock gym in over year, and probably won't ever again.

The challenge will be controlling the rate of rotation so that it doesnt spin too slow or too fast.

Maybe look at a treadwall. I think it uses some kind of hydraulic governor that is manually adjustable.

How ever the speed control gets done, I dont think its trivial.

You would also have to create some mechanism to adjust the drag on the wheel as well so you could control what angle you're climbing at otherwise you're going to be under the wheel on the bottom the whole time. To get as far up as that guy is would def require some resistance on the axle.

After a bit more thought here is a guess at speed control.

1. Closed loop hydaulic system with pump and needle valve.

2. Chain drive from wheel to hydraulic pump.

3. Needle valve adjusts allowable flow rate which then limits rate of rotation of wheel.

One more item on the treadwall to copy is an optical sensor at the bottom that stops rotation when your foot breaks the beam. Kinda like what you see on garage doors. That way you can just hang if needed.

Mr. Wonderful seems to have some wonderful idears!

With a 9' radius, it seems like it might not be steep enough for good training.

You might want to look into magnetic resistance, it's what true blue auto-belay devices use. Basically you have a conducting plate spinning in a strong magnetic field, either make one from supermagnets and an aluminum or copper plate or steal the load cell off a magnetic bike trainer. Gear it up so that provides the proper resistance. The benefit is that the rate of spin will be independent of load, that is, a heavier person will rotate at the same speed as a lighter one..

Michael C wrote:This is really cool. But I'd rather climb outside. I'd rather climb 30 feet of crap rock outside than a wheel of plastic holds inside, any time. But it's still really cool, and definitely awesome for some folks. But I'm done with plastic. I haven't set foot in a rock gym in over year, and probably won't ever again.

Awesome response. Really helpful.

Thanks for the thoughts.

Don't get me wrong, obviously I would love to only climb on real rock. Although I am lucky to be in California there isn't real rock close enough to get regular sessions. This is to make sure I am strong enough when I actually get out to Tahoe or Yosemite.

It seems we have some real engineering minded people on here, great!

I googled a picture of what I mean:

this placed on the end of the spinning axle.

In theory if I let go of the wall when the weight has lifted of the ground the wall will want to spin backwards. Changing the weight on the end will change the height I can climb to before it starts spinning. More weight will counteract me more thus allow me to get higher but also will get me away from the overhang.

Oh and to get there before someone else does: I know that Treadwall and Freedomclimber are commercially available but as a lowly public school teacher the cost is NEVER going to be justifiable (although if anybody would like to sponsor one I wont say no :))

hikingdrew wrote:You might want to look into magnetic resistance, it's what true blue auto-belay devices use. Basically you have a conducting plate spinning in a strong magnetic field, either make one from supermagnets and an aluminum or copper plate or steal the load cell off a magnetic bike trainer. Gear it up so that provides the proper resistance. The benefit is that the rate of spin will be independent of load, that is, a heavier person will rotate at the same speed as a lighter one..

I was also going to suggest this. The mechanism you're describing is eddy current damping. However, your last statement is not correct. The eddy current will induce a constant torque as a function of rate of rotation, but a heavier person will require a higher torque to keep the wheel from accelerating. A heavier climber will rotate proportionally faster than a lighter climber. Still a good, reliable, and low-wear solution though.

I had thought of using the magnetic braking after seeing it used in bike home trainers.
Any other issues people are seeing?

Trying to decide to pull the trigger and start building or just reside myself to 4 moves at a time.

I'm pretty sure you should hook up a generator to that thing so you can power your own stereo or something. maybe you could design some sort of brake like on the drum hoists they use for mining...it would allow you to kind of adjust speed

drum hoist

I know they would use wood for the brake pads...

Kris Holub wrote: I was also going to suggest this. The mechanism you're describing is eddy current damping. However, your last statement is not correct. The eddy current will induce a constant torque as a function of rate of rotation, but a heavier person will require a higher torque to keep the wheel from accelerating. A heavier climber will rotate proportionally faster than a lighter climber. Still a good, reliable, and low-wear solution though.

You are correct, I have mis-remembered my physics. Eddy current braking alone will cause constant velocity, but the braking vs load is linear. The true blue autobelay has some additional trickery to provide constant braking vs load:
autobelay.com/technology/