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Who else would like to see more wide cams on the market?
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By DannyUncanny
From Vancouver
Sep 19, 2012
Here, this is a bit more like what a cam would actually look like, still missing the full trigger mechanism though. The sling would have to be a fair bit longer I think.

The design shown here has a range of 6" to 11" using an effective min friction coeff of 0.25, (approx 14 deg cam angle). The curve of the inner lobe is calculated numerically using a stepsize of 0.01 rads based on the offset loading point. The trigger pull curve is designed for a 2.5" pull with constant torque assuming 0 friction, so it might be a bit sticky towards the top end. The cut outs I just kind of freehanded, it was probably a waste of time. Lobes are 1/4" and axle is 1/2" OD RND TUBE. I have no idea how strong any of that actually is. Space between inner lobes is 3", probably a bit tight for most hands




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By NorCalNomad
From San Francisco
Sep 19, 2012
Ahhhh that makes sense now, good concept man. I wonder what would be the activation force on that guy, with the larger cams needing stronger springs. Yes I know it might seem like I'm stuck on this ergonomics thin, but that can seperate a design that works from a design that is great.

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By Aric Datesman
Sep 19, 2012
Fun animation, Danny!

Give some thought to how that upper bar would behave when the pairs of lobes are unequal... I think the concept falls apart there, sadly.

On a side note, except for the upper bar that's pretty much what I've been leaning towards lately (with the addition of offsetting the axle, as this improves range significantly).

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By DannyUncanny
From Vancouver
Sep 19, 2012
Aric Datesman wrote:
Fun animation, Danny! Give some thought to how that upper bar would behave when the pairs of lobes are unequal... I think the concept falls apart there, sadly.

It's only a motion constraint when you are squeezing it down. If you let go, there is no force to keep the lobes, it would just go wherever they go. If the lobes are unequal the bar would be resting a bit skewed. You could have a spring or elastic push it up out of the way when you let go. Some rollers might help reduce friction.

What do you mean by offsetting the axle? For the inner lobes there, the curve is defined solely by the load point relative to the axle. There are no more degrees of freedom. Okay nm I see what you mean, starting the curve closer in yeah that could push the range more.

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By Aric Datesman
Sep 19, 2012
DannyUncanny wrote:
Okay nm I see what you mean, starting the curve closer in yeah that could push the range more.



Yup, moving the axle away from the center of the crack and towards the side the inner lobes contact does 2 things:
1. larger outer lobes, which means more range
2. longer lever arm on the inner lobes, which means you can use a steeper spiral, which means more range

The MaxCam takes advantage of this nicely, BTW.

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By mattm
From TX
Sep 20, 2012
Grande Grotto
Just my two cents on the "MaxCam" trend. I played with the MaxCams when they were first introduced and while the concept is clever, the real world use and implementation left me cold to the design. No matter how hard I tried, they required more work/thought/care in placing then a standard cam AND the chances of a botched were seemingly much higher. The fact that you had to insert the cam and have one side of the lobes touch the rock and "Reach" over to the other side was terrible. I think the market spoke as well and that's why MaxCams became and footnote in cam evolution.

If you can't "plug and chug" a cam in desperate situations, the utility of the piece is VASTLY reduced. No one wants to be in some heinous OW and have to do anything other than push the piece in. You simply COULD NOT do that with the MaxCam.

So, for me, anything other than symmetrically deploying cams is a non-starter. It would take some SERIOUS work to convince me otherwise.

Also, while yes, these piece often can be used as a push-your-own-TR that only works for so long before you leave it behind. With wider gear, there's a MUCH greater tendency for the piece to do weird sh*t once you climb past it. Introducing less stability seems, again, a poor choice.

I'm all for thinking outside the box but beware the engineers tendency to not check in with real world users and uses. (I'm currently half way through the history of the Apollo Moon Lander and the give and take between the Engineers and Astronauts is really fascinating.) I'd seriously try and get connected with some of the better known OW players and get their input.

At the end of the day, you may just find that the best thing to make is a more refined and larger#9 C4

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By George Bracksieck
Sep 20, 2012
I agree.

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By NC Rock Climber
From The Oven, AKA Phoenix
Sep 20, 2012
tanuki
I will agree also. Lot's of great ideas here, but IMHO the "Max Cam" concept is not that easy to use.

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By Aric Datesman
Sep 20, 2012
Before you all pass judgement on the MaxCam-esque design, be aware that it will likely behave *very* different from a MaxCam due to having only a single axle rather than three independent ones, and probably no stem.

I'm thinking I'll simply hack apart one of my #2 MaxCams for proof of concept and see how it places and if the stemless design avoids the flop problem (which is what I personally believe is what kept them from catching on), as it would avoid having to do the calculations and model new lobes. Then again, I might actually have lobes for this designed already and tucked away somewhere. Will look tonight.

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By NorCalNomad
From San Francisco
Sep 20, 2012
dis

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By Aric Datesman
Sep 20, 2012
Ranar wrote:
dis


-agree?

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By Aric Datesman
Sep 20, 2012
Well, digging through my archives it looks last I played with this MaxCam-esque thing was Nov'11 - May'12, and the only models I built were 0.75BD / 1MaxCam sized. Given how long I've been thinking about it I think I'll finally get around to hacking apart my extra #2 MaxCam to see what it does, as chances of me getting out climbing anytime soon are slim (1 year into restoring a 1820's schoolhouse, and need to get it finished).

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By mattm
From TX
Sep 20, 2012
Grande Grotto
Aric Datesman wrote:
Before you all pass judgement on the MaxCam-esque design, be aware that it will likely behave *very* different from a MaxCam due to having only a single axle rather than three independent ones, and probably no stem. I'm thinking I'll simply hack apart one of my #2 MaxCams for proof of concept and see how it places and if the stemless design avoids the flop problem (which is what I personally believe is what kept them from catching on), as it would avoid having to do the calculations and model new lobes. Then again, I might actually have lobes for this designed already and tucked away somewhere. Will look tonight.

I wondered about how the lack of 3 axels would affect things. That was a major cause of the MaxCam issues.

With no stem, how do you provide predictable loading of the cams and prevent off angle loads? A cam with no stem, even canted a little bit seems like it would have all sorts of issues with loading out of plane from the lobes themselves? Being sure that the forces hit the cam correctly seems important (see Link Cam). Even the Totems have a quasi-stem to direct the cable loading in the correct direction.

I have ZERO time behind cam design Aric so shoot any of these concerns down if indicated by your testing

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By Aric Datesman
Sep 20, 2012
FWIW, Matt, I'm not certain how Danny's pic above will behave either. But it looks remarkably like the idea I was batting around months/year ago and aside from the trigger is sound mathematically.

I've spent a lot of time with MaxCams, as my rack is mainly MaxCams and Zeros and frankly like them a lot provided they're used under 75% expansion. The rock where I climb is highly featured and rather Gunks-like (Eastern PA), so the offset stem is handy on occasion and there's been more than several placements I initially place the corresponding C4 and then replaced it with a MaxCam that fit the ruggedocity better. Out West, yeah, I can see MaxCam's not being ideal and found myself placing large Tricams instead (I'm on of *those* people). That said, my main concern out West was the flop issue in parallel cracks when placed towards the end of their expansion. Not entirely confidence inspiring, and this soft-goods-on-the-inner-lobes thing in theory does away with this issue.

Following from that, having a soft goods connection between the inner lobes means that there's no longer a reason for 3 separate axles and ultimately it reduces to a Totem Cam with a pair of Totem lobes connected in the center and regular lobes on the outside. I don't believe this idea falls under either the MaxCam or Totem patents, but would need to look closer if it were to become an issue (we're still batting the design for this around).

Anyway, I think this idea is worth pursuing through the mock-up stage at least, especially in the ultra-wide sizes where there's (physically) room for silly ideas for trigger mechanisms. If you don't mind, humor me for a bit while we work though the single axle MaxCam idea to see if it's worth pursuing. Depending how the single axle pushes, it might just be the cat's meow for OW TR.

-a.

(ps- does this mean you and I have buried the hatchet like USN and I did a couple months ago? I seem to recall you piling on when that went south, and would be pleased to find it trickled down... :-) )

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By NC Rock Climber
From The Oven, AKA Phoenix
Sep 20, 2012
tanuki
Not passing judgement, just giving my opinion. If it came off as negative, that was not my intent. If you understand the issues that folks have with the Max Cam and found a way to deal with them, GREAT! I am excited to see what you come up with and 100% support your innovative thinking.

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By Aric Datesman
Sep 20, 2012
No prob, NC Rock. Was just poking Matt in a friendly way as last I heard from him was less than pleasant during my blowup with USN. USN and I are good now, so now hoping Matt and I can also bury whatever it is I offended him with as well. :-)

EDIT- just occurred to me.. is there a NCRockFencer? I might have mistaken you for someone else ages ago, and if so my apologies. The NC is the part that stuck in my head, and (years later) I realize you might not be the one I butted heads with! :-O

Long story short, I've got a rather single tracked/ADHD mind and when deep into a project can come off as a dismissive asshole. Been working on that a while, and want to make amends.

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By NC Rock Climber
From The Oven, AKA Phoenix
Sep 21, 2012
tanuki
I don't know any NC Rock Fencer. You and I did have some words during the end of your tenure at rc.com, but that was years ago. No hard feeling here, and I hope that there are none on your end. Seriously wish you the best with this project and I am looking forward to seeing the final product.

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By Aric Datesman
Sep 21, 2012
That was you????????

Kidding, we're all good. :-)

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By mattm
From TX
Sep 21, 2012
Grande Grotto
We're good. All recent discussion has been much more civil across the board for all parties so no issues with me.

And please don't take my critiques here the wrong way. I'm just adding my POV to the collective knowledge.

Looking forward to a good project here

Aric Datesman wrote:
FWIW, Matt, I'm not certain how Danny's pic above will behave either. But it looks remarkably like the idea I was batting around months/year ago and aside from the trigger is sound mathematically. I've spent a lot of time with MaxCams, as my rack is mainly MaxCams and Zeros and frankly like them a lot provided they're used under 75% expansion. The rock where I climb is highly featured and rather Gunks-like (Eastern PA), so the offset stem is handy on occasion and there's been more than several placements I initially place the corresponding C4 and then replaced it with a MaxCam that fit the ruggedocity better. Out West, yeah, I can see MaxCam's not being ideal and found myself placing large Tricams instead (I'm on of *those* people). That said, my main concern out West was the flop issue in parallel cracks when placed towards the end of their expansion. Not entirely confidence inspiring, and this soft-goods-on-the-inner-lobes thing in theory does away with this issue. Following from that, having a soft goods connection between the inner lobes means that there's no longer a reason for 3 separate axles and ultimately it reduces to a Totem Cam with a pair of Totem lobes connected in the center and regular lobes on the outside. I don't believe this idea falls under either the MaxCam or Totem patents, but would need to look closer if it were to become an issue (we're still batting the design for this around). Anyway, I think this idea is worth pursuing through the mock-up stage at least, especially in the ultra-wide sizes where there's (physically) room for silly ideas for trigger mechanisms. If you don't mind, humor me for a bit while we work though the single axle MaxCam idea to see if it's worth pursuing. Depending how the single axle pushes, it might just be the cat's meow for OW TR. -a. (ps- does this mean you and I have buried the hatchet like USN and I did a couple months ago? I seem to recall you piling on when that went south, and would be pleased to find it trickled down... :-) )

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By DannyUncanny
From Vancouver
Sep 21, 2012
Here is another fun animation playing around with the renderer. I changed things around a little bit, getting rid of redundant overconstraints on the stops, and offsetting the axle from the middle just a bit. Range is about 6" to 11.5". I tried shifting it way over, but the lopsidedness got kind of out of hand.

I thought about the trigger bar a bit, and the best I could come up with was a slightly elastic tether running through the main axle to the ends of the trigger. Either that or a sliding wire or bar, but then you end up with an extra thing sticking out. The third alternative is to turn the outer lobe contacts into an enclosed slot that has enough freeplay to keep the trigger in place but still allow the two lobes to be at different positions. Anyways I've attached the excel sheet that drives the basic design.

The axle is now almost 0.75" with the lobes press fit onto wide bushings for better buckling resistance and that also serve to space them apart.



curve excel sheet

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By Aric Datesman
Sep 21, 2012
You know, Danny, move that spiral for the retraction bar in a bit and you've got one hell of a cam stop.

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By DannyUncanny
From Vancouver
Sep 21, 2012
It aready acts as a cam stop the way it is now.

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By Aric Datesman
Sep 21, 2012
Actually, it does, doesn't it? With it free floating like that perhaps constraining it a bit more would be more reassuring?

Seems to me constraining it on the other lobe would reduce loading on it compared to loading on a spiral. Food for thought.

(edit to fix phone typos)

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By Cultivating Mass
Sep 22, 2012
Leading on the only "fair means" rack.
I have a feeling that cam design is going to keep developing quite a bit over the next few years. Some pretty far out design ideas on here.

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By Aric Datesman
Sep 22, 2012
Quick and dirty mock-up using a #2 MaxCam. Seems to push ok, and no amount of wiggling the red cord makes it move, let alone flop. I kinda like it, actually.


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