5 point harness not letting go

GubNi

GubNi

8 lug disc brakes?
Joined
Mar 20, 2005
Location
Jonesborough, TN
So last week I flipped the buggy on it's lid. No big deal, right? I shut off the motor and unlatched my harness. My right side belt and right shoulder strap came off, but my crotch strap and left side stayed on. My left ball was being crushed and I couldn't get loose until someone came to help. If there had been fire this would have been bad. Has anyone else had this problem and what did you do?

I generally put it on left shoulder, crotch, and then right shoulder. Maybe I should change that order?
 
Did they always act up, or just start? I'd spray some sort of spray lubricant in them.
 
I guess its a cam-lock harness? I've never liked those, seems like once they get dirty, they start to hang up.
 
Id say it is likely just a result of the design. The tab likely got wedged at an angle in the slot of the crotch strap and didn't fall out. Not sure there is much you can do there to fix/remedy that, if so.
 
Wow.... I crashed this weekend at the Ultra4 race and ended mostly upside down. Same thing happened to me: right shoulder and lap let loose, left shoulder, left lap and crotch strap wouldn't break away.

Latch style.

Very scary, especially since a small Boulder broke the welds on my window net pinning me slightly against the seat.

It took me every bit of 60 seconds or more to loosen the shoulder strap to finally get free. Not my first time upside down, and in the past the harness released like it should have.

Interested to see what advice comes from this thread- mine is burr free.
 
I'm pretty sure mine are crow and also burr free. If the left side was angles rather than square that would promote sliding loose.
 
GubNi said:
If the left side was angles rather than square that would promote sliding loose.
Click to expand...

Angles or not, you were in a situation where the upper and lower straps were both under load, and if those two straps are under load and the plates are close together then they load the central plate in shear and it can't come free. That's not really common, but it's probably not hard to replicate when you're hanging from the harnesses so the two left straps are loaded in opposite directions.

It's like supporting something heavy from an eye hook attached to a cable using a shear pin, and trying to pull the shear pin free under load.

Sure, cam locks can get dirty, but they don't have that shear release problem.
 
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So if you look at that picture, visualize what happens when the left and sub belts are loaded in opposite directions, and won't let the left side lap plate pull out from between them because it's loaded in shear.

It would be extremely unlikely for the right side to be loaded symmetrical to the left at the same time, so the right side would likely always release without fail when upside down, etc.
 
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That's not necessarily true, as it would be easy to still have enough friction to bite and bind along the angled sides. But it would likely reduce it from happening as easily.
 
Fabrik8 said:
View attachment 217774

So if you look at that picture, visualize what happens when the left and sub belts are loaded in opposite directions, and won't let the left side lap plate pull out from between them because it's loaded in shear.

It would be extremely unlikely for the right side to be loaded symmetrical to the left at the same time, so the right side would likely always release without fail when upside down, etc.
Click to expand...
Would putting both shoulders, then the crotch, then latching help to prevent this?

I know that's not the normal way, and not the way I do it, but I'm following along for sure.
 
Mac5005 said:
Would putting both shoulders, then the crotch, then latching help to prevent this?

I know that's not the normal way, and not the way I do it, but I'm following along for sure.
Click to expand...

Under the same load directions, that may just cause the right shoulder to not release. The normal way is fine, and it's a strange combination of loads and directions that would cause the left sides to not release.

Maybe roll the vehicle onto the other side next time so it won't happen. :D
 
I have Crow harnesses in my buggy and RCI in my drag car and the RCI brand is very difficult to get everything stacked in and has little to no movement after latching, the Crows mate up easily and latch easily. Maybe the (for lack of a better word) slop in the Crows could cause a bind by allowing the individual straps to get slightly angled. The RCIs almost "pop" open when I pull the release lever. Just my observation.

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Some sanctioning bodies specifically say no camlocks, I do not know why but have seen it in rulebooks.

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