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doktor_g
Apr 29, 2007, 6:58 AM
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Gear historians?
Who made the first mass marketed SLCD Tube chocks (like Big Bros)?
Mine have "MH" stamped in the side and they're old.
Grover
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kimgraves
Apr 29, 2007, 12:35 PM
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I remember Yvion Chouinard and Tom Frost making them at the Great Pacific Iron Works in the 70's. They're dead simple, but only had two modes of placement: end to end or in an appropriate constriction. But of course they came out too easily. The new hexes were a big improvement.
Best, Kim
Edit: Opps, I guess I should read the questions prior to answering. 
(This post was edited by kimgraves on Apr 29, 2007, 10:26 PM)
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unreleasedenergy
Apr 29, 2007, 1:39 PM
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Mountain hardware made some of the early ones.
probably why yours have MH stamped on them.
I'm not sure who made the first ones.
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ja1484
Apr 29, 2007, 2:11 PM
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AFAIK, and I could be wrong on this, the first *spring loaded* tube chocks *were* BigBros, invented by Craig Luebben and sold as a design to Trango.
Now, non-active tube chocks had been around for ages before then, made by scads of manufacturers along with a lot of average joes in machine shop sheds in their back yards.
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vegastradguy
Apr 29, 2007, 2:40 PM
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Big Bros started out as Mountain Hardwear gear (Luebben designed), and then later became Trango (i cant remember if they were sold under an intermediate label between those two, though).
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gunkiemike
Apr 30, 2007, 9:14 PM
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A BigBro is neither a "chock" nor a SLCD.
But I'm glad to see someone was able to get past this errant jargon to answer your Q.
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dharmatreez
Apr 30, 2007, 10:19 PM
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i think i remember the original big bro to be Craig's engineering thesis/project in college.
but i could be wrong...
jae
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ja1484
Apr 30, 2007, 11:07 PM
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gunkiemike wrote: A BigBro is neither a "chock" nor a SLCD. But I'm glad to see someone was able to get past this errant jargon to answer your Q.
A BigBro is definitely a tube-chock. As you can see here on Trango's website:
http://www.trango.com/prod.php?id=34
The manufacturers themselves refer to them as a "tube chock design".
So you're wrong there. But I love you anyway.
As it happens, it is spring loaded, but you are correct that it's not an SLCD as there isn't any camming involved in it's operation.
So, 1-1 for today.
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roy_hinkley_jr
Apr 30, 2007, 11:38 PM
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Well if you're going to be pedantic...a BigBro does in fact work by camming not wedging. And it is spring loaded. So it is indeed an SLCD. Tube chocks work by wedging and have no spring, so they are chocks.
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ja1484
May 1, 2007, 12:42 AM
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roy_hinkley_jr wrote: Well if you're going to be pedantic...a BigBro does in fact work by camming not wedging. And it is spring loaded. So it is indeed an SLCD. Tube chocks work by wedging and have no spring, so they are chocks.
You may be right, but I'm not sure I see how. As far as I'm aware the active phase of a BigBro involves sizing it to the crack and then locking it at that length. Pulling on the chock once set does absolutely nothing in terms of it's action.
As a matter of fact, the entire point of the spring expansion of a BigBro is that the chock can be sized so that it wedges in the crack, eliminating the need to built tube chocks to order or hope the ones you have fit some constriction or another on the climb.
So, please elaborate on your position. Camming involves a downward force being translated to a lateral force exerted by lobes on the device. BigBros neither have lobes, nor translate downward pull to outward force. They just wedge, because they're tube chocks, albeit tube chocks with adjustable size.
I maintain my position: BigBros are tube chocks, not SLCDs.
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shockabuku
May 1, 2007, 12:48 AM
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ja1484 wrote: roy_hinkley_jr wrote: Well if you're going to be pedantic...a BigBro does in fact work by camming not wedging. And it is spring loaded. So it is indeed an SLCD. Tube chocks work by wedging and have no spring, so they are chocks. You may be right, but I'm not sure I see how. As far as I'm aware the active phase of a BigBro involves sizing it to the crack and then locking it at that length. Pulling on the chock once set does absolutely nothing in terms of it's action. As a matter of fact, the entire point of the spring expansion of a BigBro is that the chock can be sized so that it wedges in the crack, eliminating the need to built tube chocks to order or hope the ones you have fit some constriction or another on the climb. So, please elaborate on your position. Camming involves a downward force being translated to a lateral force exerted by lobes on the device. BigBros neither have lobes, nor translate downward pull to outward force. They just wedge, because they're tube chocks, albeit tube chocks with adjustable size. I maintain my position: BigBros are tube chocks, not SLCDs.
Why do you suppose the cord is offset and not centered like a nut? One end is positioned as a fulcrum and as the cord pulls down on the other end the tube rotates into position in a camming action. It's like trigonometry.
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ja1484
May 1, 2007, 1:04 AM
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shockabuku wrote: ja1484 wrote: roy_hinkley_jr wrote: Well if you're going to be pedantic...a BigBro does in fact work by camming not wedging. And it is spring loaded. So it is indeed an SLCD. Tube chocks work by wedging and have no spring, so they are chocks. You may be right, but I'm not sure I see how. As far as I'm aware the active phase of a BigBro involves sizing it to the crack and then locking it at that length. Pulling on the chock once set does absolutely nothing in terms of it's action. As a matter of fact, the entire point of the spring expansion of a BigBro is that the chock can be sized so that it wedges in the crack, eliminating the need to built tube chocks to order or hope the ones you have fit some constriction or another on the climb. So, please elaborate on your position. Camming involves a downward force being translated to a lateral force exerted by lobes on the device. BigBros neither have lobes, nor translate downward pull to outward force. They just wedge, because they're tube chocks, albeit tube chocks with adjustable size. I maintain my position: BigBros are tube chocks, not SLCDs. Why do you suppose the cord is offset and not centered like a nut? One end is positioned as a fulcrum and as the cord pulls down on the other end the tube rotates into position in a camming action. It's like trigonometry.
Not according to Trango's instructions:
http://www.trango.com/pdfs/BBInfoSheet.pdf
But I'd love for you to convince me otherwise. Feel free to give it a shot, but you're going to have to come up with some really good evidence to hold water.
EDIT: As I understand it, the cordage sling is off to one side to prevent the tube from abrading it as the chock is collapsed. I don't believe it has anything to do with any camming action for two primary reasons:
- BigBros can be placed vertically if conditions permit, and direction of pull is not necessarily rotational in this situation and
- The tube length is already, supposedly, locked off by the screw collar when the chock is set. In an ideal placement, further expansion of the chock is not necessary.
But again, feel free to prove me wrong. I like to know when I'm wrong. Helps me get it right.
(This post was edited by ja1484 on May 1, 2007, 1:11 AM)
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vegastradguy
May 1, 2007, 1:10 AM
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ja1484 wrote: shockabuku wrote: Why do you suppose the cord is offset and not centered like a nut? One end is positioned as a fulcrum and as the cord pulls down on the other end the tube rotates into position in a camming action. It's like trigonometry. Not according to Trango's instructions: http://www.trango.com/pdfs/BBInfoSheet.pdf But I'd love for you to convince me otherwise. Feel free to give it a shot, but you're going to have to come up with some really good evidence to hold water.
um, thats exactly what the instructions note- the cord is on one side of the bro.
bros arent placed perfectly horizontal, they're placed at a slight angle [the ends of a bro are not straight, they're set at opposing angles]- the cord is on the uphill side of this angle- when you fall it pulls down and the bro cams into the rock to hold.
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ja1484
May 1, 2007, 1:14 AM
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Well, you could be right. I'll give it the benefit of the doubt. But I would see this as more of a passive camming action a-la tricams, the spring not being involved (unless it's a loose placement, and I wouldn't want to trust that).
So what shall we call it then? A spring loaded camming tube chock? SLCTC? That's a mouthful.
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gunkiemike
May 1, 2007, 1:41 AM
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(aw jeez...look what I started...)
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