I been looking at biner failures for long time and recently I reviewed the UIAA test page that offers several films related to biner failures during pull test. it seems to me that locking pin on the gate does not appear to catch the hook during shock load or pull test.

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 ?

[URL=http://imageshack.us][IMG]http://img357.imageshack.us/img357/7801/bentcarabine22bh8.jpg[/IMG]

If so, then why in many causes, the applied tension causes the pin and the hook not to interlock ?

I been looking at biner failures for long time and recently I reviewed the UIAA test page that offers several films related to biner failures during pull test. it seems to me that locking pin on the gate does not appear to catch the hook during shock load or pull test.

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 ?

[URL=http://imageshack.us][IMG]http://img357.imageshack.us/img357/7801/bentcarabine22bh8.jpg[/IMG]

I been looking at biner failures for long time and recently I reviewed the UIAA test page that offers several films related to biner failures during pull test. it seems to me that locking pin on the gate does not appear to catch the hook during shock load or pull test
....
If so, then why in many causes, the applied tension causes the pin and the hook not to interlock ?

The way I see it, the pin and the little hook do nothing. Basically, they are both worthless and I am pretty confident that, this is the biggest Screw-up in the history of climbing gear design and yet, manufactures are still making them with the same problem

The pin does not interlock with the hook under tension period. If the hook is there to stop the gate from bending backward (extend travel) then they could just cut the notch and keep the hook straight like a regular Chinese key chain biners .

If the notch is there to interlock with the biner then our great mechanical engineer who keep designing these biner should know that applied tension to the axis line causing the lower part of the biner to bend as well which eventually shift the angle of the hook to miss the pin by 0.00001 (whatever distance) .

Would it be logical to design the shape of the hook (or the gate) in a way that engages with the pin not at its normal (unloaded condition) but during the loading phase so it could actually engages with the pin to keep the gate closed?

Alright, I am waiting for the climbing manufacture engineers to explain this myth here.


[URL=http://imageshack.us][IMG]http://img522.imageshack.us/img522/521/81798928iq1.jpg[/IMG]

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?

The way I see it, the pin and the little hook do nothing. ....

The pin does not interlock with the hook under tension period.

Like others said - the notch on the first biner was taped, so it is the open gate test.

For the second biner, the footage starts with the biner already stressed and the pin past the notch. So probably the gate was held open while the biner was stressed and then let go, once it could not engage the notch. Maybe they were just trying to save on tape? :-) Deceptive editing - perhaps their marketing people were in charge?

Conclusion: both are open gate tests. Perhaps they should be more clearly marked as such, but there was really no descriptive text attempted in these video clips.

Majid, are you just trolling, or are you serious that the notch and pin do not add strength?

majid_sabet why do you make these posts?

Unless I am overestimating your intelligence you already know the answers here.

As others have said of course the pin is useful. And I dispute your claim that many cases applied tenesion causes the pin and hook not to interlock.

Of course it does! Haven't you ever sat in your harness on a carabiner in front of your face? You can watch the carabiner bend until the pin connects with the nose.

Here are some videos for you to watch:
http://youtube.com/watch?v=ZyVD0FBLiFQ
http://youtube.com/watch?v=r86a-DnHrNE
http://youtube.com/watch?v=qm49U2ZW0IE
http://youtube.com/watch?v=la0PBne7GRE

...I am pretty confident that, this is the biggest Screw-up in the history of climbing gear design and yet, manufactures are still making them with the same problem

[URL=http://imageshack.us][IMG]http://img522.imageshack.us/img522/521/81798928iq1.jpg[/IMG]

It was hard before but it is now officially impossible to take you seriously anymore.

Show me bunch of biner that shows pin got pulled out or the notch got snapped right of the biner during pull test or an actual fall then you will see if my statment makes any sense or not.

You know, you could do that too, instead of using somebody else's (totally unsubstantiated) picture of said failure. In fact, do that now.

That picture from the BD website is misleading. Nice touch to make the text too small to be readable. This is ancient fixed gear with weak spring tension and Kolin clearly states that he believes the failure is from gate flutter. It's worth noting that gate flutter never happens in a static pull like most biner loading, you need a drop test to see it. Which is exactly what BD did.

Anyone reading the patent on the keylock gate will notice that one of the stated benefit of that design is that a partially open gate can still lock into the groove.

Nitpick: The biner on the BD page is actually an OP biner, not BD.

The biner is anything but new and drop tested. I don't know about you but I've had to manually close gates on fixed biners because the spring couldn't do it. I hardly believe that this case is representative of a production biner in good condition.

Show me an example of a new biner with solid gave and hook nose (like a quicksilver) being tested in a drop test. Then you'll have something to take about. I've bent open-gate biners with short body weight falls before but not a biner who's gate was properly closed when loaded.

I see that you're an idiot. It matters that the biner spent the last few years hanging around someone's project and being rained on and so on. Because that biner is not representative of an average biner in good mechanical order. You attack my nitpick because you've got nothing substantive to say to back up your claim.

If you want your idiotic assertion (that the pin does nothing) to have any credibility at all, it's a really easy test to run. Take a set of identical carabiners, cut the pins out of half of them, and pull test them. I can gauran-goddamned-tee that the ones with the pin will hold larger loads before breaking.

Just because the failure mode doesn't usually involve breaking the pin does NOT mean that the pin is useless.

STFU

is that clear ?

Majid

Most of us think that the reason that pictures of broken carabiners around only show intact pins is because it is very, very difficult to create enough force in a climbing situation to exceed the measured carabiner closed gate strengths. 'All' of the field failures are open gate failures - bad springs, gate flutter, rock pressure, .... And so they have intact pins.

It should be pretty easy for you to show whether the pins engage or not - grab a couple of volunteers, jumars or prussics, and by the time you get the third guy on the line, you will be able to see the pin engage or pass the hook. Use an assortment of connections - biners, 8mm, 15mm, 25mm tape, cord... Tell us if you can get it to miss, and how.

Thanks.

The pin does not interlock with the hook under tension period.

Yo majid a cursory google revealed this link on the 2nd hit. You may be interested in this:

http://web.mit.edu/...gue_Presentation.pdf

They even have some majid-like illustrations! They even speak to your specific topic. This study seems to conclude that plastic deformation of biners occurs in low-load scenarios early in a biner life, and that plastic deformation can cause the pin to misalign later, during a fall.

Very interesting piece. Some new stuff in there for me personally.

As to the persistance of the pin/notch design, for many years Kong owned the patent on keylock designs and licensed that technology to Petzl, Spirit biners. No other mfg. had license to make them. My cursory understanding is the patent expired and now nearly ever mfg produces keylock designs.

I would not buy new pin/notch biners as my primary biner anymore. I prefer keylocks and wiregates. The prices aren't so much of an object anymore either, due to competition. Used to be that keylocks were TWICE what pin/notch designs were. For 50 biners that was a shitload of money. A SHITLOAD.

There's your why's. Enjoy!

DMT

DMT

Yo majid a cursory google revealed this link on the 2nd hit. You may be interested in this:

http://web.mit.edu/...gue_Presentation.pdf

Listen
If you do not have mechanical engineering background of some sort nor you understand how metal work and react during taking load then I would suggest you to keep your unwanted comments out of LAB and allow someone else who has the knowledge or the background to come forward in to this serious discussions.

You should take your own advice. I'm a physicist with quite a bit of experience backing my claims up with real data. You never do anything that would pass as even remotely meaningful in a scientific publication. Posting a bunch of pictures out of context and pretending like they support your ludicrous assertions is at best naive and at worst maliciously misleading.

You're a tool and should stay FAR, FAR away from the lab.

thanks DMT!
just as i said, majid you are onto something, but try to stay a bit more friendly, mkay?

qwert

Yo majid a cursory google revealed this link on the 2nd hit. You may be interested in this:

http://web.mit.edu/...gue_Presentation.pdf

They even have some majid-like illustrations! They even speak to your specific topic. This study seems to conclude that plastic deformation of biners occurs in low-load scenarios early in a biner life, and that plastic deformation can cause the pin to misalign later, during a fall.

there are few people here in RC who continuously keep calling me names when they can not prove their points .

So rather than the gate pin being useless (Majid) it is actually one of the stronger parts of the biner.

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

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.

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.

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.

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

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?

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

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?

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 ?

No. That's what the spring does. The notch/pin keeps the biner from deforming (trolls to the contrary notwithstanding.)

GO

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.
...

You've clearly never done much aid climbing. I can get the pin to engage the hook on most biners merely by weighting the thing with my body and a full wall rack plus rope drag. Cannot open the damn biner till I take some weight off it. Somewhhere in the neighborhood of 300-400 pounds if memory serves.

DMT

hell, pick up just about any biner and pull with your bare hands. yea thats right. your eyes didnt fool you. the gate/notch moves---



---now how safe do you nancies feel.



---better go back to knittin.

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.

Does it interlock the same way when you take a fall with load been applied in all direction ?

I think gr4t nailed the point. the pin is crucial. it should be weaker than a strait section of biner under a tension load. however, because on most modern biners the load is moved to the spine to concentrate the load on the spine and reduce the bending load. bending loads are typically difficult to support with nice sleek compact shapes. the lever arm to the elbows is reduced by putting the loads closer to the spine. because the gate and pin are farther from the spine, their lever arm is further and greatly reduces the bending load on the elbows. this is why biners are so many times stronger closed than open.

Also, i saw something about plastic deformation. this is called creep. when a material is deformed elastically, the strain increases nearly linearly with load. in elastic deformation, the material returns to its original shape. in plastic deformation, the material retains (most of) its deformed shape. creep occurs above a certain stress level. this is where the material deforms nearly elastically then returns to a slightly deformed state with the load released.

The above is a theory, i don't have experimental or numerical proof to back it up. i do have some engineering background however, but further analysis testing would solidify the above theory.

I was also wondering if anyone knew how most biners are made. i know DMM forges their biners which i think is spiffy. are most biners made from some kind of strait stock that is bent to shape?

...
Also, i saw something about plastic deformation. this is called creep. when a material is deformed elastically, the strain increases nearly linearly with load. in elastic deformation, the material returns to its original shape. in plastic deformation, the material retains (most of) its deformed shape. creep occurs above a certain stress level. this is where the material deforms nearly elastically then returns to a slightly deformed state with the load released.

...
I was also wondering if anyone knew how most biners are made. i know DMM forges their biners which i think is spiffy. are most biners made from some kind of strait stock that is bent to shape

Most biners are made in similar format from 7000 series aircraft quality aluminum.

That's nice fluff that sounds cool. Care to explain what it means to the lay-man?

No, go research it yourself and find out what I mean.

But you're the certified aircraft mechanic. I'm just a n00b.

Yapp, Graduated from Northrop Institute of Technology in 1986 with GPA of 3.25

Dingus

not realted to our topic here but interesting to read.

http://www.bstorage.com/...o/carab/agecarab.htm

Then you should have no problem answering the question, right?

Trench

I know what you are trying to do. You are trying interrogate me in front of the RC member of the juries by cross examining some of the stuff I have said in here to prove that MS is wrong which I do not mind as long as you support your pervious statements. Now, to help you out of this miserable situation, why do not you just take the leadership and buddy up with the rest of wabbit bashing party and take this matter one step farther to the RC management and ask them to completely delete this post cause you do not see any reliable data to satisfy you.

Don't cry, dude... I just wanted to know what 'aircraft quality aluminum' is. I guess you can't answer that.

Back to the original point then...

Have you any comments on the stress-strain plots I linked that show that gate contact increases the slope of the stress-strain curve by a factor of three? Is that not enough evidence to show that the gate of the carabiner significantly impacts the strength of the carabiner?

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][IMG]http://img166.imageshack.us/img166/8813/screenhunter001iw7.jpg[/IMG]

[URL=http://imageshack.us][IMG]http://img148.imageshack.us/img148/525/screenhunter002qz5.jpg[/IMG]

You already know what AC quality aluminums are therefore; I see no point of trying to explain or cover the area because it is to related to this particular topic.

As far as how strong the gate is or it can, well you make the gate as strong as its possible by using other materials such as different compound or other metals like Titanium but still, the two pins on the side of the gate and the hook on the biner side dictates how strong the gate is . You can modify the hook to engage with the pin and do a perfect direct pull test where you know for sure that you got 100% hook-pin engagement but I will guarantee you that biner gate will fail due to following causes;

1- Broken pin at the either side of the gate
2- By a crack at the hinge side of the gate which causes the gate to come off
3- Or by broken hook.

The way I see it, the pin and the little hook do nothing. Basically, they are both worthless and I am pretty confident that, this is the biggest Screw-up in the history of climbing gear design and yet, manufactures are still making them with the same problem

The pin does not interlock with the hook under tension period. If the hook is there to stop the gate from bending backward (extend travel) then they could just cut the notch and keep the hook straight like a regular Chinese key chain biners .

During static loads the spring makes your proposed modification useless.

During dynamic loads, you modification would prevent the nasty effects of gate flutter, only if the gate tries to snap open after the carabiner has stretched enough for the hook to prevent the pin from getting dislodged. I don't know if this would be the case, in most gate flutter events.

Trench

Answer me this

What is the purpose of the lock on a locking-biner ?

A-is to stop gate flutter
B- To prevent the gate/hook misalignment
c- I do not know what to say
D other reason like.......................

first: I'm not trenchdigger.
second: this is condescending.
third: when a lock is in place, flutter would be impossible, hence forcing the gate/hook into alignment.
fourth: what are you trying to prove at this point? Is it that a key lock designed gate is better? I think so. Let's stop talking around that, and just talk about it.

Key locks are better.