[討論]自鎖功能的使用迷失

[ccchien1973]

作者: IC

https://www.blackdiamondequipment.co...toblock-misuse

這篇文章源自 IC 大哥在其它討論給的一個連結. 這個連結之前曾中斷(bad connection)過一段時間, 昨天突然想參考裏面的內容, 沒想到這個連結竟然又活過來了 (欣喜!)
有鑒於之前的中斷, 與同樣的情形發生在板上的其他文章 (很多先前文章裏的連結都中斷了, 因而, 失去了很多重要的參考資料, 覺得甚為可惜, 所以決定, 乾脆把整篇文章複製, 貼到板上.

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QC Lab: Autoblock Misuse

Lately I’ve been getting quite a few questions on the use of the Black Diamond ATC-Guide and/or similar “autoblock”-style belay devices—and another installment of QC with KP was born. I’ve seen some curious/scary autoblock uses/misuses out there and I had the boys in the QA lab test a couple of the setups I’ve seen, which were:

a) Incorrectly using a standard belay device as an autoblock device.
b) Using multiple biners as the “brake bar” in order to make taking in rope easier.

1. INCORRECTLY USING A STANDARD BELAY DEVICE AS AN AUTOBLOCK DEVICE

An autoblock-type belay device is awesome for belaying up one or two people on a multi-pitch route. When used correctly (utilizing a SOLID anchor, threaded correctly, always having your brake hand on the rope, etc) it is easy to take in rope and lock one or both strands should the seconding climber(s) happen to fall. However, I think the recent popularity in these devices has caused some confusion. A few weeks ago I was at Red Rocks on a super classic (read: crowded) route belaying my partner as he led upward. A climber below us joined me at the belay ledge and set up his belay system by equalizing the two-bolt anchor with a cordelette (the tie-in point was at chest height) and used a standard ATC device as an autoblock. I politely suggested that the belay setup wasn’t ideal as the belayer would need to raise their arm up above their chest (see photo) in order to lock off the climber, and they may not be able to hold the fall. The climber assured me that they “do this all the time” and that the seconding climber wouldn’t fall anyway because the climbing was “so easy.”

Incorrectly setting up a standard belay device off the anchor, 見圖一.

Now whether this was a case of not understanding exactly how an autoblock device works, I’m not sure. I hope that it’s obvious to most people reading this that when using a standard belay device as described above it DOES NOT LOCK automatically if a second falls, and is VERY DIFFICULT to hold the climber by hand if he/she were to weight the rope. When using a standard belay device to bring up a second, I always belay off my harness’ belay loop, with the rope running through the anchor as a directional—that way if the seconding climber were to fall, the load is on the anchor. Some people belay off the harness straight down to the climber, but in the case of a fall, the belayer is now being yanked off the ledge and being pulled in two directions (the belayer is tied off to the anchor, but the pull from the fallen climber is downwards).

The correct setup of an autoblock device, 見圖二.

2. USING MULITPLE BINERS AS THE “BRAKE BAR” IN ORDER TO MAKE TAKING IN ROPE EASIER

I’ve had a few people write me claiming that, while using an autoblock device such as the ATC-Guide, they get pumped taking in rope when belaying their seconding climber up. It’s true that pulling up fat ropes (i.e. 10.5 mm and greater) has increased friction and therefore requires more effort than pulling up skinny cords. So other than not using such a fat rope, what are the options to make life a little easier? Well, I’ve had several people claim that they use multiple carabiners as the brake bar to help save the pump, but they’re worried about the potential loss of locking ability should their seconding climber fall. So I asked one of the members of the crack-crew of QA engineers here at Black Diamond to run a few quick, unofficial tests using two of our most popular models of locking carabiners, the RockLock (rounder cross section) and the VaporLock (flatter cross section). Here are the results:

Take-Up Force Measurement, 見圖三.

Take-Up Force:

Carabiner Quantity & Style / Take-Up Force (lbf)
1 RockLock / 25
2 RockLocks / 29
1 VaporLock / 28
2 VaporLocks / 35

In the testing we did, using multiple (two) biners actually INCREASES the amount of force required to take rope in.

* I believe this is because though the radius of the rope going over at the top of the device is larger, the radius at the bottom, where the rope pinches, is tighter. As well, I think multiple biners are assisting in forcing the rope harder into the grooves of the device, therefore causing more friction and thus more force required to take up rope.
* What the data also showed is something that is pretty intuitive and many have noticed and realized in the field: the shape of a biner’s cross section had an impact on the amount of take-up force required. (i.e. round cross section biner = easier to take rope in; flat cross section biner = harder to take rope in).


Holding Force Measurement, 見圖四.

Carabiner Quantity & Style / Holding Force (lbf)
1 RockLock / 1218
2 RockLocks / 1316
1 VaporLock / 1466
2 VaporLocks / 1825


We found, once again in the limited testing we did, that using two biners actually INCREASES the amount of holding force.

* Once again, for the same reasoning, though the radius the rope takes at the top of the setup is larger and you would think reduces the amount of holding force, the multiple biners cause the radius at the bottom of the setup, where it clamps on itself in the device, to be tighter and therefore INCREASES the holding force.
* And once again, the data showed that flatter cross section biners had a greater holding force than rounder cross section biners.


What is the ultimate solution? You need to find a balance that works for the given situation. I’m usually climbing on anywhere from two 8.1s, to a single 9.1 mm, 9.7 mm or even a 10.2 mm. I typically use a VaporLock (flatter cross section) when using skinnier ropes, and a RockLock (rounder cross section) when using fatter ropes.

Again, this is pretty rough stuff; as always don’t take it as the Gospel. More in-depth testing would need to be performed to come to any concrete conclusions. I’m sure there’s a point where more biners would reduce the take-up force and reduce the clamping force. Is it three biners? (No, because we tested that…) Could it be four or five? Not sure, as we didn’t take it that far. And it goes without saying that I’m not a climbing guide and I don’t even play one on TV. If you want official instruction get it from a qualified, certified instructor.

Climb safe out there,

KP

[ccchien1973]

這個連結不但可以連上了, 而且裏面的文章也做了部分修改, 和新增了第二部分的內容. 整體上, 感覺是一篇比先前還好的文章.

文章的第一部分:

跟先前的內容一樣, 主要是說: 先鋒者爬完路線做上方確保時, 把不具自鎖功能的 ATC 直接掛在固定點上, 且掛得位置太高 (約在胸部), 如此不符合人體工學 (確保者的手要抬得更高, 才能做出確保動作), 因而有可能無法承受 seconder 墬落時的衝擊力, 所以不安全.

Black Diamond提出的解決方法有二:
其一, 把 ATC 掛在 belay loop 上做確保, 主繩在經過 anchor, 作一個 directional 來改變施力的方向. 其二, 把 ATC 換成有 autoblock 功能的 ATC guide.


文章的第二部分:

有ATC Guide的使用者抱怨, 當使用自鎖功能時, 需要用很大的力氣才有辦法收繩, 甚至用力到手臂會有 pump 的感覺. 於是, 有人提議說, 扣兩個勾環在 ATC Guide上當 Brake Bar, 似乎可以減少摩擦力, 而讓收繩容易一點. 所以, Black Diamond 做了以上量測 (請見原文).

量測的大致結論是: 多放一個勾環只會增加摩擦力, 不管是在"收繩", 或是在"負重"(負seconder重量)的情況下. 且摩擦力跟勾環的切面形狀(Cross Section)和曲率(radius)有關, 當用比較圓型切面與曲率小的勾環時, 可以降低摩擦力. 也就是說, 當你使用比較粗的主繩時 (或覺得摩擦力太大), 可以搭配比較圓型切面的勾環 (如原文中的 BD RockLock 勾環), 反之, 當你覺的摩擦力不足時, 就可以使用比較扁平切面的勾環 (如文中的VaporLock) 來增加所需的摩擦力.

但根據原本的數據, 如果都只使用一個勾環, RockLock 跟 VaporLock 兩者間, 收繩的力量也只差了 3 磅 (lbf), 約減少了 12% 的摩差力, 這差別似乎說大也不大, 說少也不少. 真得少了這 12%, 收繩時, 手就不會 pump 了嗎?

不過, 這篇文章也有可能解決了我心中的一個疑惑, 雖然我不是用 ATC Guide, 但我的 Reverso 也有摩擦力過大的問題 (當搭配10.2mm 主繩時), 或許我也可以試試不同的勾環, 或許情況也會有所改善!

最後, 原文中也提到, 這只是初步的量測結果, 未來需要有更多的實驗數據, 才能下更明確的結論. 在此, 只是提供給大家參考一下! 請斟酌使用!

[ccchien1973]

自覺標題有點怪: 自鎖功能的使用迷失? 應該是"迷思"! 或乾脆說 misuse!
唉......英文沒進步多少! 中文卻已經退化到國小程度!
請大家包涵!

[neihu]

9/16am0530跟攀朵拉的阿奇繩隊爬石碇岩壁.2pitch.50m

我用atc guide也有摩擦力過大的問題(我用過reverso.atc.yoyo...)
就慢慢收.手甩甩就ok!然後...

最後我用義大利半扣lower阿奇下降
我在把兩條接好漁人結.用atc guide雙繩下降回到地球!!

[ccchien1973]

作者: ccchien1973

量測的大致結論是: 多放一個勾環只會增加摩擦力, 不管是在"收繩", 或是在"負重"(負seconder重量)的情況下. 且摩擦力跟勾環的切面形狀(Cross Section)和曲率(radius)有關, 當用比較圓型切面與曲率小的勾環時, 可以降低摩擦力.

原文中的曲率(radius), 應該是指: 繩子穿過 ATC Guide 時的轉折程度, 而不是我上述的 "勾環的曲率". 也就是, 掛不同數目的勾環, 會造成繩子在確保器上的轉折程度不同, 進而影響到繩子穿過確保器的摩擦力.

當初沒看清楚, 不好意思!

[ccchien1973]

作者: neihu

9/16am0530跟攀朵拉的阿奇繩隊爬石碇岩壁.2pitch.50m

我用atc guide也有摩擦力過大的問題(我用過reverso.atc.yoyo...)
就慢慢收.手甩甩就ok!然後...

最後我用義大利半扣lower阿奇下降
我在把兩條接好漁人結.用atc guide雙繩下降回到地球!!

我要看照片! 我要看照片!

根據內湖兄的使用經驗, 你覺得 ATC Guide 跟 Reverso 相比, 那一個在自鎖的模式下, 比較難收繩?

[neihu]

reverso比較好收繩!

[mount3092]

作者: ccchien1973

不過, 這篇文章也有可能解決了我心中的一個疑惑, 雖然我不是用 ATC Guide, 但我的 Reverso 也有摩擦力過大的問題 (當搭配10.2mm 主繩時), 或許我也可以試試不同的勾環, 或許情況也會有所改善!

Eric 恕刪部分主文
ATC Guide 與 Reverso 3無論在單繩距或是多繩距傳統攀登,假若用在上方確保,也就是將確保器直接掛在Fuco Point, 或是master biner上時候,Reverso 3可以用比較細的繩子,這樣在收繩時候,摩擦力比較小,那麼ATC Guide可以使用較粗的繩子.

會有這樣的不同,我想是她們在設計上的口徑大小,以及寬度所造成的差異性,但都是很好的確保器,尤其在從事多繩距攀登時候.

sorry 我教練有依他們個人guiding經驗,提及該適用範圍,但我沒有很仔細記住數字,所以無法提供詳細的粗系數字

[ccchien1973]

感謝貫中兄的經驗分享, 如果 Reverso 比較好收繩, 那我應該就不考慮購買 ATC Guide了!

此外, Edgar在這裡提出一個很有趣的觀點, 如果我沒有理解錯誤的話, 應該是指: 若想減少收繩時的摩擦力, Reverso 可以搭配比較細的繩子, 但 ATC Guide 反而應該要用粗一點的繩子.

後者的做法似乎跟直覺相衝突, 請問是不是因為, 就如你以上所提的, 跟確保器的設計(鎖死/咬合機制)有關? 謝謝分享!

很想實際做做實驗, 可惜沒有那麼多不同的確保器與不同粗細的主繩.

[mount3092]

To Eric
今日訓練課程結束後,我特地就ATC Guide and Reverso 3,再向教練請教.回答大約如下.Reverso 3因為他本身設計"外型上"關係,使用較細的繩子收繩上,會比較順暢,也就是摩擦力比較小,但是當然妳的繩子是粗一點的,也是可使用,只是說摩擦力比較大,那當然收繩比較累.ATC Guide粗細繩使用上都是ok的,沒有粗繩比較好,細繩比較不好,

所以相較之下,若是你的繩子偏粗,那當然是ATC Guide讓你收繩會比較快且順暢,若是繩子偏細,那這兩種確保器使用上沒有很大差異性

但以上的敘述都僅限於,使用於auto lock的狀況下,若是使用一般的確保方式,不是使用auto lock的狀況則無差異性

PS.若是你同時有這兩種auto lock的確保器,你可以仔細觀看""穿繩孔的長度""(Sorry我沒有去找原場說明,希望你可以懂我在說哪部分)以及"穿繩孔的寬度"尺寸上有些許不同

[ccchien1973]

原來是這樣! 感謝 Edgar 的分享與說明!