/ New Cam Design
Any comments on the design/ things that need to change would be helpful. The main comments so far are how would this work with just 1 hand. I'v been chatting with some of my tutors and have got an idea of how to make it one handed.
Here's what I have so far. Just 3D modeling. Photobucket link hope it works.
Also I found out the other day that a similar idea already exists.
I'v read through all the comments.
Seems to me that a force pulling on the stem would cause the cams to come closer together, and so the outward force on rock would be lost and it would fail. Maybe it's the diagrams but if they are correct implies a serious flaw.
Looking at your design, I think that the long rigid stem will be problematic with forces which are not aligned with the stem.
You could alleviate this by having hte stem fixed at the lower bracket and able to extend above the top bracket - if that makes sense.
I'm still concerned about off centre forces though.
Have you ever heard of a big-bro? I am not sure I would trust your device over one
or a kong gypsy?
both are novel and distinctive approaches to the problem of wide cracks
In reply to A Game of Chance:
> Seems to me that a force pulling on the stem would cause the cams to come closer together, and so the outward force on rock would be lost and it would fail. Maybe it's the diagrams but if they are correct implies a serious flaw.
Yes, it needs a massive spring (or some other type of mechanical wizardry) between the lower arms and the krab attachment point
In reply to Wot:
That'll be £50,000 please.
I'got lectures so back later. And yes UKC will have to in the bibliography
There are various suggestion for stem adjustments in the other thread that will work one handed and as well as if not better than a thread/nut. The problems you have (and they're the same for all the stem variations) are stability of placement when the cams are well spread and the very high mechanical advantage achieved at small expansions. Of course you can limit it with stops but then you also lose quite a bit of range which is the only real selling point.
Out of curiosity, are I-beams the best structure for resisting buckling? And shouldn't the I-beams all go to a pair of common axles top and bottom to avoid applying bending loads to the stem (which can then be lighter or possibly even flexible)?
What is the actual aim of the project?
Looks like a decent idea but you've ignored the problem of stability. Big cams are very prone to falling out due to twisting motions of the head.
If you look at a plan view of a typical 4-cam, the length of the axle is usually greater than the width of the largest placement it can be used in (more so in smaller cams, from 3 up its typically squarish). This gives it the stability your design will lack.
Seems to me the design is not really for a climbing cam, it's more for something to lock in a crack with smaller, more aligned loads than you get in a climbing fall. Climbing cams take large loads and adjust well when the load is perfectly aligned and are beautiful designs in that respct. Start looking at the stresses and limits of response in your structure when loaded with realistic forces found in climbing and you'll see problems: to make it strong enough and deal with non-aligned loads it soon gets too big/heavy.
Why are the top and bottom arms dissimilar lengths? Surely there's no real merit in arranging the thing so the stem can be either in compression or tension depending upon the user setting, it makes the adjustment locking much harder and will result in excess stem/adjuster weight. It's a guess but I'd have thought designing it so the stem is always in tension will provide the simplest lightest solution.
it's just very hard to do in solidworks.
Don't complain about solidworks some of us are still battling on with autocad!
I'm redesigning it when I get the chance (a lot of other work to do). Had a Q&A with some of my tutors over it and they picked up on loads of mistakes. Not even to do with climbing, just material/wear and how it's all gonna fit together. 3rd year's hard :)
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