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gr4t
Mar 12, 2008, 1:56 AM
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majid_sabet wrote: antiqued wrote: majid_sabet wrote: The way I see it, the pin and the little hook do nothing. Basically, they are both worthless ] Majid - if that is the case, how do you explain the different test results - open gate vs closed gate? Is this involved with biners that have a pin or a gate that comes with a locking latch? In either way, I like to see pin breaks, bent, snap or the hook come off before the biner begin to bend. Here check out this film http://www.theuiaa.org/act_safety.html
Yes, you have open vs closed gate strengths on biners with pins. The quicksilver reports a closed gate strength almost 3 times as strong as the open gate strength.
http://www.bdel.com/..._detail.php#techtips
The problem with the UIAA video is even if the 2nd biner is a closed gate test, you don't see the measure of force applied when the biner deforms to the point where the gate opens, this could be at a much higher force than the breaking point in the first open gate test with the obviously taped notch.
So I see three primary failure modes that don't involve a failed pin or notch.
1. at a higher force than the open gate breaking failure force the biner bends enough to disengage the pin from the notch, the gate opens then the biner breaks.
2. the pin stays in place and does not fail and the biner breaks at the elbow near the spine. Which makes some sense given that the biner is designed to take more of its load along the spine than along the gate - so the pin and nose may not see enough force to break or deform before the bend in the biner.
3. the gate come open, due to gate flutter or contact with another object, or your hypothesis that the pin is worthless, allowing the biner to bend and break under a lighter load.
You, of course, will see more pictures of biners that break by mode number 3, because the open gate strength is so much lower, and the closed gate strength at typically above 20kN is much more difficult to generate in standard climbing situation.
I haven't seen anything to make me believe that in all of those falls where the biner doesn't break the pin does not seat properly in the notch contributing to the overall strength of the biner.
-Carl
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irregularpanda
Mar 12, 2008, 3:11 AM
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Majid,
qwert wrote: you have some good ideas and interesting thoughts, but the way you write your stuff makes it very hard to read, or even take seriously. maybe you really know a lot about that stuff you are talking about, but wiht your "i know everything and you dont" approach you arent making new friends. and for those that dont want to be your friend, but want to gain knowledge in the lab, you make it very hard to take you seriously.
Yeah, basically. I fall into this latter category, as in I don't care about you guys as long as you don't injure yourselves, but would like to learn more in the lab..... It also makes it difficult when your original post is poorly phrased and misleading. You start it out with questions, and (sort of) imply how much more you know than others. Then, when I try to think about your original question which was:
Does this pin and the hook do anything useful ?
Does it increases the biner KN strength by any amount if pin catches the gate?
If so, then why in many causes, the applied tension causes the pin and the hook not to interlock?
it makes almost no sense. It's all fun and games to get in pissing contests on the interweb, I'm guilty as charged, but your approach provokes a pissing contest almost every time. It's basically just odd how you provoke these pissing contests, and then consistently become reactionary towards the consistent flamings you recieve. OK, now that was everything.
Aside from that, I love reading lab forums and learn a bunch from them.
(This post was edited by irregularpanda on Mar 12, 2008, 3:12 AM)
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Valarc
Mar 12, 2008, 4:02 AM
Post #53 of 234
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majid_sabet wrote: Your stuff my be good in the classroom but out there I know my stuff. You should contact the MIT guys and get busy with them supporting my facts.
Right, they will get right on it, after they are done proving that cold fusion produces a net energy gain, the moon landing was faked, and that gravity is caused by an invisible chain of plastic monkeys. We scientists like to start with the least ridiculous "theory" and work our way up from there.
You have no facts. Let me repeat that.
You. Have. No. Fucking. Facts.
You have a completely asinine hypothesis with some random pictures to "support" it. Several people, whose real life experience greatly outweighs your own, have said flat-out that they have experienced the pin being directly engaged on a regular basis. You have conveniently ignored those posts, however, and keep spouting your "I know more than you" bullshit, the same as you do in every one of your ridiculously stupid threads.
I've met first-day college kids taking their belay class who understood the basic physics of climbing gear better than you do.
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reg
Mar 12, 2008, 12:35 PM
Post #54 of 234
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madjid - this is good stuff - it's made me realize there exsists a fault in design of the bent gate biners. i won't use them any more. as someone else mentioned earlier it seems the oval biners may - because of their symetery - allow the pin to engage when under extreme loads. wadaya think?
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trenchdigger
Mar 12, 2008, 3:05 PM
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reg wrote: madjid - this is good stuff - it's made me realize there exsists a fault in design of the bent gate biners. i won't use them any more. as someone else mentioned earlier it seems the oval biners may - because of their symetery - allow the pin to engage when under extreme loads. wadaya think?
The shape of the gate has no bearing on the likelyhood of the notch catching the pin of the gate.
If the oval carabiner design is so far superior, why are then rated and tested at significantly weaker strengths?
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reg
Mar 12, 2008, 3:45 PM
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well it seemed to me when watching the vids and thinking about majid's post that when high loads are applied to the bent gate biner, the knotch pulls out and away from the pin thus negating that connection.
don't really know the answer to ur 2nd question - maybe different material or added structures like gusseting. R
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Roasta
Mar 12, 2008, 3:47 PM
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trenchdigger wrote: reg wrote: madjid - this is good stuff - it's made me realize there exsists a fault in design of the bent gate biners. i won't use them any more. as someone else mentioned earlier it seems the oval biners may - because of their symetery - allow the pin to engage when under extreme loads. wadaya think? The shape of the gate has no bearing on the likely hood of the notch catching the pin of the gate. If the oval carabiner design is so far superior, why are then rated and tested at significantly weaker strengths?
Trench, I guess I was speculating about ovals on the basis that they may have more potential to cause the direction of pull/load to be parallel to the spine keeping the notch in play a little longer.
I figure ovals are also weaker due to this trait of centering the load. Where as a bent gate tends to direct (is designed to) the rope into the bucket - closer to the spine, less leverage; hence an increase in strength.
On the other hand if the direction of load, in a bent gate (or oval to an extent) was occurring on the gate side of the bucket; wouldn't this flex the bucket more and hence move the notch away from the gate? This is hard to simulate with a draw on the biner but with cord/rope it is easier to see a 'diagonal' load occur.
Only my theory, feel free to pick apart.
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dingus
Mar 12, 2008, 3:55 PM
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There is no need for emotional attachments to the pin/notch design, yo! There are superior designs on the market now and they are affordable. Pin/notch has its benefits (cheap mainly) but also has associated downside. Stress fractures around the pin holes were a MAJOR problem for a while, for example. I found several of them (stress fractured biners) on my main rack when that issue surfaced, for example.
I started using bullnose Stubais in the mid 90s and those bad boys are still in good shape. Notch gate designs are just plain superior, imo.
DMT
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Roasta
Mar 12, 2008, 3:56 PM
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edit to add: I understand the spring in the gate keeps trying to keep the pin of the gate and notch in contact up until the biner bucket flexes to far and the gate swings on its arc..... What about the idea of the gate been on a 'cammed arc' so it actually lengthens with the flex?? Obviously it will add weight and bulkiness which we don't really want on a basic and fundamental climbing item.
Just a random thought.
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dingus
Mar 12, 2008, 3:59 PM
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Roasta wrote: trenchdigger wrote: reg wrote: madjid - this is good stuff - it's made me realize there exsists a fault in design of the bent gate biners. i won't use them any more. as someone else mentioned earlier it seems the oval biners may - because of their symetery - allow the pin to engage when under extreme loads. wadaya think? The shape of the gate has no bearing on the likely hood of the notch catching the pin of the gate. If the oval carabiner design is so far superior, why are then rated and tested at significantly weaker strengths? Trench, I guess I was speculating about ovals on the basis that they may have more potential to cause the direction of pull/load to be parallel to the spine keeping the notch in play a little longer. I figure ovals are also weaker due to this trait of centering the load. Where as a bent gate tends to direct (is designed to) the rope into the bucket - closer to the spine, less leverage; hence an increase in strength. On the other hand if the direction of load, in a bent gate (or oval to an extent) was occurring on the gate side of the bucket; wouldn't this flex the bucket more and hence move the notch away from the gate? This is hard to simulate with a draw on the biner but with cord/rope it is easier to see a 'diagonal' load occur. Only my theory, feel free to pick apart.
I seem to recall an article somewhere that detailed the process of breaking open and closed gate biners, and the difference between straight-backed and ovals.
The key is understanding that in traditional stock-gate biners (as opposed to wiregates) is that the gate is the weakest part of the biner. As the load increases toward failure the biner DOES bend and eventually the pin/notch disengage and the biners back breaks. At least that's how memory serves.
Straight-bcked biners, offset D's in particular, transfer more of that load from the gate to the spine, allowing the gate to remain engaged to higher loads before eventual failure. Ovals split the load equally between spine and gate, therefore fail under lower loads.
That's my story, I'm sticking to it till someone corrects me!
DMT
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trenchdigger
Mar 12, 2008, 4:01 PM
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dingus wrote: There is no need for emotional attachments to the pin/notch design, yo! There are superior designs on the market now and they are affordable. Pin/notch has its benefits (cheap mainly) but also has associated downside. Stress fractures around the pin holes were a MAJOR problem for a while, for example. I found several of them (stress fractured biners) on my main rack when that issue surfaced, for example. I started using bullnose Stubais in the mid 90s and those bad boys are still in good shape. Notch gate designs are just plain superior, imo. DMT
Good points indeed, but you're getting way off into the rough here. The argument here is that the shape of an asymmetric carabiner causes the gate pin to fail to catch the notch. That's simply not true.
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dingus
Mar 12, 2008, 4:16 PM
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trenchdigger wrote: dingus wrote: There is no need for emotional attachments to the pin/notch design, yo! There are superior designs on the market now and they are affordable. Pin/notch has its benefits (cheap mainly) but also has associated downside. Stress fractures around the pin holes were a MAJOR problem for a while, for example. I found several of them (stress fractured biners) on my main rack when that issue surfaced, for example. I started using bullnose Stubais in the mid 90s and those bad boys are still in good shape. Notch gate designs are just plain superior, imo. DMT Good points indeed, but you're getting way off into the rough here. The argument here is that the shape of an asymmetric carabiner causes the gate pin to fail to catch the notch. That's simply not true.
You know I don't give a shit about majid's theories. Going off into the rough is my GIG man, its MY GIG!!!111
DMT
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trenchdigger
Mar 12, 2008, 4:27 PM
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dingus wrote: You know I don't give a shit about majid's theories. Going off into the rough is my GIG man, its MY GIG!!!111 DMT
True... true. In that case, carry on.
.
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majid_sabet
Mar 12, 2008, 4:52 PM
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reg wrote: madjid - this is good stuff - it's made me realize there exsists a fault in design of the bent gate biners. i won't use them any more. as someone else mentioned earlier it seems the oval biners may - because of their symetery - allow the pin to engage when under extreme loads. wadaya think?
Reg
The pin-hook engagement design on the oval biner apparently is the best and make it superior to all the other biner out there and this due to fact that during tensioning phase, the load ( B) is evenly divided along the both side ( A) of the biner .
However, the oval biner are weaker and have lower KN than r D shape biner cause the strongest part of the biner is along the axis line (C) but when oval biners are loaded , the forces are applied away from the axis line and more in center.
When D shape biners are loaded, majority of forces are applied in one side causing the lower part of the biner (D) to bend in an angle. Since the gate side of the biner is not fixed and has a gap (between pin and hook), the hook side (F) also move to an angle of its own causing the pin or the hook to not engage or even if they engage, they would pop out.
This problem becomes even worse when the applied tension on a “D” shape biner moves away from the axis line and stay in the middle on the biner or closer to the gate side.
[[URL=http://imageshack.us]
(This post was edited by majid_sabet on Mar 12, 2008, 4:59 PM)
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trenchdigger
Mar 12, 2008, 5:04 PM
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dingus wrote: I seem to recall an article somewhere that detailed the process of breaking open and closed gate biners, and the difference between straight-backed and ovals. The key is understanding that in traditional stock-gate biners (as opposed to wiregates) is that the gate is the weakest part of the biner. As the load increases toward failure the biner DOES bend and eventually the pin/notch disengage and the biners back breaks. At least that's how memory serves. Straight-bcked biners, offset D's in particular, transfer more of that load from the gate to the spine, allowing the gate to remain engaged to higher loads before eventual failure. Ovals split the load equally between spine and gate, therefore fail under lower loads. That's my story, I'm sticking to it till someone corrects me! DMT
Agreed.
I haven't seen failure tests for notchless (dovetail gate) carabiners, but I'll bet their failure mode is the same. I'll bet lockers fail in a similar way with the locking sleeve getting destroyed in the process.
Different notch/dovetail shapes could effect how long the pin/dovetail stays in contact, and i'm sure that has been factored into the carabiner design. There is a limit to how deep a notch can be made without causing other usability issues with the design.
One thing that can effect the likelyhood of the pin catching the notch in a shock loading situation is the mass of the gate. "Gate flutter," as we like to call it, is a noteworth danger supporting the choice of wire gate carabiners as a potentially safer option.
If you're still not convinced that the gate contacting the carabiner does anything to add strength, check out the charts on slides 17-21 in this presentation.
http://web.mit.edu/...gue_Presentation.pdf
While you're at it, read through the intent of the presentation and see why fatigue is not an issue with carabiners used in climbing.
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Roasta
Mar 12, 2008, 5:06 PM
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So while we are out in the 'rough', disregarding the asymmetric and symmetric debate; would it be fair to say that under normal climbing loads (not lifting or catching huge amounts of weight or force) the notch/hook serves more of a purpose of keeping the gate closed and therefore less chance of our rope escaping? Same concept as notch less biners having a longer sleeve down and over the nose of the biner; just keeps the gate closed/rope in longer...
Going on the high KN ratings that are been produced in tests when the gate and notch separate, I think my body being crushed may be more to be worried about. Once my sphincter becomes my mouth I don't really care about the biner snapping. 
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dingus
Mar 12, 2008, 5:51 PM
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The pin doesn't engage the notch until the biner deforms under load, otherwise we couldn't open or close the biners without applying force to the gate. There would be an audible click as well.
As I said before I have repeatedly caused the pin to engage the notch by standing on biners with big wall loads. The reason the pin is engaged ie because the biner has deformed under that load.
That's pretty much how they are designed for work deform slightly, engage the pin, to prevent massive deformation under working loads. Eventually they don't spring back so well and the biner gets retired.
I've deformed keylock biners too, through various uses both ligit and out-of-scope. They get difficult to open and close too as a result.
I think its prudent to retire ANY biner with a clicky gate.
DMT
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majid_sabet
Mar 12, 2008, 6:07 PM
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dingus wrote: The pin doesn't engage the notch until the biner deforms under load, otherwise we couldn't open or close the biners without applying force to the gate. There would be an audible click as well. As I said before I have repeatedly caused the pin to engage the notch by standing on biners with big wall loads. The reason the pin is engaged ie because the biner has deformed under that load. That's pretty much how they are designed for work deform slightly, engage the pin, to prevent massive deformation under working loads. Eventually they don't spring back so well and the biner gets retired. I've deformed keylock biners too, through various uses both ligit and out-of-scope. They get difficult to open and close too as a result. I think its prudent to retire ANY biner with a clicky gate. DMT
Dingus
When you were standing on the biner, was it a D shape or an Oval ?
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dingus
Mar 12, 2008, 6:18 PM
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majid_sabet wrote: dingus wrote: The pin doesn't engage the notch until the biner deforms under load, otherwise we couldn't open or close the biners without applying force to the gate. There would be an audible click as well. As I said before I have repeatedly caused the pin to engage the notch by standing on biners with big wall loads. The reason the pin is engaged ie because the biner has deformed under that load. That's pretty much how they are designed for work deform slightly, engage the pin, to prevent massive deformation under working loads. Eventually they don't spring back so well and the biner gets retired. I've deformed keylock biners too, through various uses both ligit and out-of-scope. They get difficult to open and close too as a result. I think its prudent to retire ANY biner with a clicky gate. DMT Dingus When you were standing on the biner, was it a D shape or an Oval ?
Hmmmm, oval for the most part. I don't like using Ds on my aiders for all the usual reasons. The D's I know I've engaged were bullnosed keylocks, haha. I can't specifically recall engaging a modern asymetrical D pin/notch... I know I engaged the old classic BDel D's, the ones with all the stress fractures. Like the one in that MIT presentation. Those biners sucked, on balance.
But all that is purely anecdotal and the product of a hazy memory fog as well. Good luck on your jihad!
DMT
(This post was edited by dingus on Mar 12, 2008, 6:19 PM)
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majid_sabet
Mar 12, 2008, 6:25 PM
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Dingus
I can't go in to Jihad with these guys. They are not hardcore enough to go head to head with Sorbat. Anyway ,I had a feeling you were using Oval on aiders cause it is easier to lock the gate on oval vs D when stepping on it due to fact that your load is evenly distributed on each side (assuming you buy this theory).
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Roasta
Mar 12, 2008, 6:56 PM
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cracklover wrote: Roasta wrote: would it be fair to say that under normal climbing loads ... the notch/hook serves more of a purpose of keeping the gate closed and therefore less chance of our rope escaping? No. That's what the spring does. The notch/pin keeps the biner from deforming (trolls to the contrary notwithstanding.) GO
Good point... that is kind of what I am trying to say; that by stopping (prolonging) the deformation keeps the gate in play, making the biner stronger but also keeps the gate closed.
The spring's function only works while the biner is a closed circuit as such. Hence the need for the notch/pin to catch the gate before it swings on it's arc.
So in my opinion the notch and pin is not 'useless' (as we agree) and serves a few purposes either directly or inadvertently.
a) Provides extra strength (up until the point the force is so great that all of the biners properties would probably be toasted anyway)
b) Is required to help keep the 'closed circuit' with the gate contacting the nose and therefore rope security.
c) and in the case of the pin and hook design: it is a PITA when it hooks on everything!
Still interested in the impact of applying the load closer to the gate - causing more flex and maybe taking out the hook/pin functionality earlier. Pretty hard to simulate and very dependent on biner shape. Refer to Majid's pic: I mean that 'F' point would go out and down rather than down and back towards the spine - kind of grabbing the gate on its way. As a biner is not a circle it is pretty hard to get this load on the diagonal in an equal and opposing way; unless the sling, cord or what ever gets caught up near the gate/nose side rather than sliding down into the curve or bucket of the biner.
I am (and was) happy that the notch etc does have a purpose as stated above. Figured as much seen as though the brainy dudes who invented and continue to improve on the basic concept still keep the hook and pin concept in some sort of format. Everyone is always looking for ways to save money in production - so if it was a 'useless' concept I think they would have scrapped it a long time ago.
(This post was edited by Roasta on Mar 12, 2008, 7:21 PM)
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majid_sabet
Mar 12, 2008, 7:30 PM
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IMO, the notch (hook) design should be shaped much like what is shown on image A than B assuming you do not cut too much from the side of the hook.
[URL=http://imageshack.us]
[URL=http://imageshack.us]
(This post was edited by majid_sabet on Mar 12, 2008, 7:34 PM)
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trenchdigger
Mar 12, 2008, 7:54 PM
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dingus wrote: The pin doesn't engage the notch until the biner deforms under load, otherwise we couldn't open or close the biners without applying force to the gate. ...
Exactly...
Again, I reference the MIT charts: http://web.mit.edu/...gue_Presentation.pdf.
The charts specifically show the impact of the gate pin engagement of a D shaped 'biner on the stress-strain curve in slide 20.
Another interesting slide is #18 which shows that after the first loading cycle, some plastic deformation occurs. Consecutive cycles show almost no additional plastic deformation until failure. What does that mean? Well, it means there's a limit to how deep you can make the indent in the notch to catch the pin as Majid is suggesting. Make the indent in the notch too deep and the plastic deformation will essentially lock the carabiner. It may hold a little more force before failure, but after put a significant load on it, you won't be able to open it unless you can compress it enough to clear the pin past the indent in the notch.
(This post was edited by trenchdigger on Mar 12, 2008, 7:56 PM)
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