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Klippan seatbelt install question

Started by _SLR Goat_ , Oct 10 2012 07:20 PM

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22 replies to this topic

#1 _SLR Goat_

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Posted 10 October 2012 - 07:20 PM

In the process of fitting klippan brand front seat belts in the torana and following the instructions that came with the belts it says to bolt the reel mount and front lower mounting plate on the same bolt hole like in the picture posted below will this be okay i could bolt it to the factory mounting point further forward just as easily

cheers in advance for any info
Posted Image

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#2 _greenmachine215_

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Posted 10 October 2012 - 09:49 PM

That's pretty much how I put mine in,

and in saying that I thought these seat belts were a load of shit in regards to "fitment" I had to drill out the holes on the anchor points and pivot spacers, use original mounting bolts cos the threads supplied were different ect, but apart from nothing really being a direct fit the seat belts themselves operate very well.

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#3 StephenSLR

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Posted 11 October 2012 - 12:02 PM

Personally I'd use the factory bolt hole, in an accident you have the force distributed between four anchor points not three.

A shame they come with that elongated mount but my guess is it'll be hidden away.

s

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#4 _torbirdie_

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Posted 12 October 2012 - 01:23 AM

Personally I'd use the factory bolt hole, in an accident you have the force distributed between four anchor points not three.

A shame they come with that elongated mount but my guess is it'll be hidden away.

s

Steve the force isn't divided up between four anchor points, it's really only three, the two floor ones on the side of the car and the one on the trans tunnel side.
The tunnel side gets 50% and the side ones 25% each

The upper pillar mount does experience a force due to its redirection action, but doesn't reduce the force on the floor mounts.

Brings up an interesting point though on the safety of retrofitting inertia reel setups to cars that initially weren't engineered for them. The klippan instructions are obviously for those that only had fixed belts and rely on the one floor mount on the side of the car.

The inertia real type actually doubles the force that would be seen on the upper pillar and the floor mount and whether the mounts have been engineered for this on say an LJ is anyone's guess.

Would it be ok to use the one mounting pt in those where there are two floor mounting points. My best reckoning would be yes as possibly to meet standards the one point should be able to take all the force from that side which could happen if the belt became knotted on either side of the buckle. Best to use the to mounts if the geometry of that ridiculous extra metal piece allows it.

Drilling out the fittings so they fit, don't think you'll find anyone from klippan will put it in writing that is ok, personally, I'd pay the extra mula and get the originals recond.

Or buy 2nd hand.....I've got a few in the shed that need to go.

Edited by torbirdie, 12 October 2012 - 01:32 AM.

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#5 StephenSLR

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Posted 12 October 2012 - 07:51 AM

Steve the force isn't divided up between four anchor points

Think of this diagram upside down.

http://upload.wikime...Pulley0.svg.png

However because the sash (part that goes over the shoulder) isn't vertically down when you tug on the belt the upper mount will experience F + F cos θ (not accounting for friction).

Posted Image

You have to reinforce the top hole with an anchor plate and apparently on some cars you must fit an inertia reel if you're going to fit lap-sash belts. If you install a static lap-sash belt, the top mount experiences more force as there is no pulley mounted to it and this can (depending on the car) collapse the roof in. I'm not too sure about this as the bolt is meant to act in shear not tension.

Would it be ok to use the one mounting pt in those where there are two floor mounting points. My best reckoning would be yes as possibly to meet standards the one point should be able to take all the force from that side

I'd say the bolt size is over engineered and the one point can take the force but if you can, use two points.

Speaking of retrofitting, check out the work on my Mustang.

http://www.gmh-toran..._25#entry699682

s

Edited by StephenSLR, 12 October 2012 - 08:03 AM.

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#6 StephenSLR

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Posted 12 October 2012 - 09:39 AM

The inertia reel type actually doubles the force that would be seen on the upper pillar and the floor mount and whether the mounts have been engineered for this on say an LJ is anyone's guess.

Having another think about this, yes the upper mount would definitely experience an increase in force with a change from static to inertia reel with loop - not exactly double though.

Is the seat belt upper mount in the b-pillar or roof rail in an LJ?

As long as the upper mount bolt is a 7/16 and it threads through an anchor plate and not just sheet metal it should be ok.

I'm still convinced however if you mount to 4 bolts, each bolt will experience less 'trauma' in an impact than if you mount to 3 bolts.

I may have been thinking about the kinetic energy that's distributed between the four and my point is agreeing with what you're saying, let's say each lower side bolt does experience 25% each, it's better to mount to 2 lower side bolts than just one as that one bolt would then experience 50%.

s

Edited by StephenSLR, 12 October 2012 - 09:42 AM.

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#7 _torbirdie_

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Posted 12 October 2012 - 10:08 AM

Having another think about this, yes the upper mount would definitely experience an increase in force with a change from static to inertia reel with loop - not exactly double though.

Given that the angle that the occupant moves forward at in a collision is most likely going to be pull on the belt is going to be variable and even 45 represents 1.8 times the force, then doubling covers all scenarios.

I'm still convinced however if you mount to 4 bolts, each bolt will experience less 'trauma' in an impact than if you mount to 3 bolts.

I may have been thinking about the kinetic energy that's distributed between the four and my point is agreeing with what you're saying, let's say each lower side bolt does experience 25% each, it's better to mount to 2 lower side bolts than just one as that one bolt would then experience 50%.

Steve the mounting points are not removing kinetic energy(they dont get hot), they are providing a force to deaccelerate the occupant and keep them connected to the car. The kinetic energy is transferred either into the earth on braking or other objects that are collided with on braking.

Because the centre pillar mount is simply a "pulley arrangement" it doesn't change the tension in the belt, the tension on the two floor mounts is exactly the same:(25 +25) 50% of the force needed to deaccelerate the occupant. The centre pillar pulley arrangment can only decrease the force on the floor mounts if there is significant/incredible friction across the belt.

Edited by torbirdie, 12 October 2012 - 10:22 AM.

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#8 StephenSLR

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Posted 12 October 2012 - 10:19 AM

The centre pillar pulley arrangment can only decrease the force on the floor mounts if there is significant/incredible friction across the belt.

The areas where most of the loading occurs is at the upper loop and buckle.

Posted Image

The upper loop and buckle aren't exactly frictionless pulleys, would this affect the forces experienced at the floor mounts?

s

Edited by StephenSLR, 12 October 2012 - 10:20 AM.

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#9 _torbirdie_

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Posted 12 October 2012 - 10:42 AM

No there is nothing wrong with Klippans claim that the upper loop and the buckle receive the most load. what is wrong is your interpretation that the centre pillar reduces the load on the floor mounts in an inertial reel arrangement.

Steve Id consider the friction forces are way insignificant compared to the tension in the belt itself, Id hate to be relying on the friction over that smooth chrome support rather than the bolt on the floor.

But if you are adamant its enough to put into the equation, why not do some tests for yourself. Use a centre pillar mount and suspend equal weights each side of it via seat belt webbing and then by removing weights from one side find out the difference in weight needed for it to move and evaluate that as a percentage of the tension force.

Edited by torbirdie, 12 October 2012 - 10:48 AM.

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#10 StephenSLR

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Posted 12 October 2012 - 10:52 AM

Use a centre pillar mount and suspend equal weights each side

I'm not doubting pulley physics.

The diagram above has circled the load indication areas. The top mount definitely experiences load.

To do the experiment correctly one would install stress/strain gauges on the two lower mounts then put the car in an accident for test one.

Then for test two remove the top mount completely and record the stress/strain on the two lower mounts.

Getting back to my post, yes I did say 4 points as opposed to 3 but my point was referring to have two lower mounts, saying it's better to have two lower mounts than one.

s

Edited by StephenSLR, 12 October 2012 - 10:59 AM.

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#11 _torbirdie_

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Posted 12 October 2012 - 11:09 AM

The diagram above has circled the load indication areas. The top mount definitely experiences load.

??????????well yes as I pointed out initally, up to double the load that would be experienced by the floor anchors( do you accept the physics that it doesnt remove load from the floor anchors?)

To do the experiment correctly one would install stress/strain meters on the two lower mounts then put the car in an accident for test one.

Then for test two remove the top mount completely and record the stress/strain on the two lower mounts.

Very convenient Stephen, your thinking will remain correct until someone gives you two lj's to crash into a brick wall along with a test dummy?

Didnt imply that the simple static friction test I suggested was perfect, however, you could move the weights through the pulley and find the distance it takes them to stop to get an idea of the dynamic friction as well and then decide whether its really significant or not, and whether wrecking two LJs and a crash dummy is going to be necessary to come to a conclusion about the effect of friction here..

Edited by torbirdie, 12 October 2012 - 11:19 AM.

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#12 StephenSLR

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Posted 12 October 2012 - 11:26 AM

Very convenient Stephen, your thinking will remain correct until someone gives you two lj's to crash into a brick wall along with a test dummy?

Lol, yeah fair enough.

Regardless, we're straying away from my point.

The issue is the Klippan belt has an extension and two belt ends mount to the one lower point.

I was saying if you have 4 points (i.e. two lower mounts on one side) each lower mount experiences less force than just having one lower mount on the one side (where the inertia reel bolts to the same hole the belt does).

The force is still distributed between 4 points, there is definitely a force experienced at the top mount, no matter how many weights you add and subtract from it, the top mount will experience the varying force of the weights you add and subtract.

s

Edited by StephenSLR, 12 October 2012 - 11:30 AM.

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#13 StephenSLR

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Posted 12 October 2012 - 12:20 PM

what is wrong is your interpretation that the centre pillar reduces the load on the floor mounts in an inertial reel arrangement.

Ah, I've just got it, I think the above is the misunderstanding in our debate.

I didn't exactly say the centre pillar reduces the load on the floor mounts, show me where I said that. I was saying with two floor mounts, the two floor mounts each experience less load as opposed to one floor mount.

Two floor mounts = 4 points

... and by distribution of the forces I'm saying that the top mount experiences a force as well. I was confused as how you could think the top mount doesn't experience any forces.

s

Edited by StephenSLR, 12 October 2012 - 12:35 PM.

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#14 _torbirdie_

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Posted 12 October 2012 - 12:59 PM

Ah, I've just got it, I think the above is the misunderstanding in our debate.

There's no misunderstanding here Stephen

I didn't exactly say the centre pillar reduces the load on the floor mounts, show me where I said that.

No, you didnt say that exactly, but here is what you did say:

Personally I'd use the factory bolt hole, in an accident you have the force distributed between four anchor points not three.

what you have written here indicates that at the time of writing you believed that the total force necessary to arrest the occupant has distributed amongst four different points and hence that the centre pillar support by its inclusion would be reducing the forces the others need to provide.

. I was confused as how you could think the top mount doesn't experience any forces.

certainly I never implied or said anything of the sort, in fact I said it will experience DOUBLE the forces of the floor mounts.

Just digging yourself into a deeper hole. , Im done with your subterfuge here.

Edited by torbirdie, 12 October 2012 - 01:00 PM.

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#15 StephenSLR

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Posted 12 October 2012 - 01:29 PM

here is what you did say:

Personally I'd use the factory bolt hole, in an accident you have the force distributed between four anchor points not three.

and I stand by that.

You have 4 bolts instead of 3

Notice the first part of my sentence, the factory bolt hole on the floor is the extra hole I am talking about.

what you have written here indicates that at the time of writing you believed that the total force necessary to arrest the occupant has distributed amongst four different points

It is distributed at 4 separate points, the top mount, two on the lower side and the belt stalk next to the tunnel.

Lets say you have Force F1 acting on the belt.

Without the top mount, the top half of the body is pushed forward instead of remaining secure and thus increasing the Force F1 in the belt to Force F2

Since F2 is higher than F1 you have an increase in force acting on the lower mounts.

I don't know how to explain it any clearer.

s

Edited by StephenSLR, 12 October 2012 - 01:30 PM.

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#16 _SLR Goat_

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Posted 12 October 2012 - 04:25 PM

lets just agree to disagree i think either mouting hole for the lower front plate will work okay either way while wearing the belt it sits even dosent get caught or twisted and the locks work when i jolt forward

Edited by SLR Goat, 12 October 2012 - 04:27 PM.

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#17 StephenSLR

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Posted 12 October 2012 - 05:03 PM

lets just agree to disagree i think either mouting hole for the lower front plate will work okay either way while wearing the belt it sits even doesn't get caught or twisted and the locks work when i jolt forward

Sorry for the thread hijack.

I'm keen to learn more on the physics behind it.

Torbirdie's right if the tension in the belt remains constant.

I'm thinking that if you remove the top mount (lap belt situation) there will be more tension in the belt causing a greater force at the lower mounts. If that's wrong I'll accept it.

s

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#18 _SLR Goat_

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Posted 12 October 2012 - 06:34 PM

All good mate hows the band doing i think i have you on MSN messenger but i havent used it for ages

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#19 StephenSLR

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Posted 12 October 2012 - 06:55 PM

All good mate hows the band doing i think i have you on MSN messenger but i havent used it for ages

Was that you I used to chat with on MSN Messenger all those years ago?

Band is going rather quiet gig-wise, we still get together and we're working on some new material. Our drummer lives in Tweed Heads so it makes things a bit hard rehearsal wise but we slayed them at our last gig.

Here's a review

http://www.loudmag.c...ent/lycanthia-1

Cheers for the interest.

s