Upper seatbelt anchorage point

[JasonL]

Please can someone who has been through the IVA explain how the minimum height for the upper anchorage point is assessed?

I get the it's a 136x53 rectangle, but is it a block or a plate placed at the centre of the seat?

The sides of the seat in most roadster seats are higher (often much higher) than the centre, so if it was a wide block it would rest on these and would need to be much higher. It seems logical that it's a plate or a thin block, but can anyone confirm?

Explanation: I want a simple roll bar without stays or a seatbelt bar and am planning on welding a 70x70x5mm box section to the back of SB2 and across part of CP3&4 (so it projects up by 50mm) with the bosses going through each wall (outer ones through CP3/4 and the upper wall). Trouble is that it's close to the minimum 450mm.

Thoughts/issues/criticisms of my approach also welcome.

Thanks.

[flyerncle]

Look at VOSA website and IVA help it will explain more than words.

[JasonL]

Thanks, but I already did. They only give advice about strength, not position.

This is the most relevant thread I can find, but no one has said explicitly how wide/deep the block is.

https://haynes.co.uk/forums/showthread.php?p=101351#post101351

[Davidbolam]

Thanks, but I already did. They only give advice about strength, not position.

This is the most relevant thread I can find, but no one has said explicitly how wide/deep the block is.

https://haynes.co.uk/forums/showthread.php?p=101351#post101351

I have grp seats and the block was small enough to rest on the bottom. Ie not resting over the sides.

I can't remember how thick that block was though

David

[JasonL]

Thanks David,

I have about 250mm of flat base between the sloping sides.

Do you think the block was thicker/wider than that?

Thanks.

J

[Stot]

The width is not important, its a single reference point. I made this to work things out, a rough copy of what they used in the test. You put it on the seat with the lower left corner touching the base and back of the seat, then put the stick bit at 90 degrees straight up. The string should be level with the ground when measuring the anchor points. They had a bubble that hung on the string.

https://lh3.googleusercontent.com/-E7gnPnC6SKo/U8GmPw2MsjI/AAAAAAAAKSc/JVioHLPgnEk/s800-Ic42/headrest1.JPG

Mine is marked 700mm for the head rest height, you would need to have a bolt at 450mm for the anchor points.

Here I am measuring my headrest height, the stick goes parallel with the seat back for this one.

https://lh3.googleusercontent.com/-4ycchZduPH8/U8GmQanLtvI/AAAAAAAAKSk/2YUKs6wbZaA/s800-Ic42/headrest2.JPG

Cheers
Stot

[JasonL]

Spot on, thanks mate. That's exactly what I was after!

[TheArf]

Sorry to hijack this thread but I have a slightly different question about the harness mounts.
If you make the roll-bar the same as the book ones and put the cross member in at 100 mm up from the SB2, as per the book has this caused anyone a problem with the test. I have set my cross member at 100 mm to the top not to the centre and my harness appears to be horizontal to the fitting, if that makes sense

Arfon

[Badger]

I've ended up putting mine slightly higher - more through accident than design to be brutally honest! If you're using a harness with eye bolts that will raise it slightly as well, so that may make a difference.