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Rear seatbelt eye-bolt angle
craigdiver - 13/10/17 at 09:55 PM

I have a roll hoop which has a cross-member which will have the threaded bosses welded into it for the upper seatbelt mounts. The seatbelts clip into eye bolts which are screwed into the bosses. Am I better welding the bosses vertically making the eye bolt pull sideways (shear force?) or am I better mounting the threaded bosses angled towards the seatbelt so the force is trying to pull the threads out of the boss?

Any thoughts?

[Edited on 13/10/17 by craigdiver]

daviep - 14/10/17 at 08:52 AM

Eye bolt is far stronger inline than at an angle, for lifting applications eye bolt rating is reduced to 25% of safe working load when pulled at 90degrees, i.e. 1000kg eye bolt is only good for 250kg at 90 degrees to the thread. I would presume the theory is the same regardless of application.

In practice I guess it doesn't matter as the majority of harness mounting points in real life tend to be at 90 degrees e.g lap belts down the side of seats or shoulder straps on to the top of bar behind seats.

If using at 90 degrees they should be orientated so that the hook pulls on the side of the ring as opposed to the top of the ring, use a thin shim below eye bolt so that orientation is correct when the eye bolt is tight, if you need shim give me a shout.

Regards
Davie

Angel Acevedo - 23/10/17 at 01:52 PM

If you reach eyebolt breaking limit, you may be dead already...
I would think surrounding structure will be the limiting factor...
Or the belts...



quote:
Originally posted by daviep

If using at 90 degrees they should be orientated so that the hook pulls on the side of the ring as opposed to the top of the ring, use a thin shim below eye bolt so that orientation is correct when the eye bolt is tight,...

Regards
Davie


A small O ring may act as a shim and it would give some adjustability..
Once you install the belts, the eyebolts canīt unscrew.
HTH

loggyboy - 23/10/17 at 02:09 PM

MSA state sheer is preferable to traction:

craigdiver - 23/10/17 at 02:30 PM

quote:
Originally posted by loggyboy
MSA state sheer is preferable to traction:


I can understand the logic behind this for a tab mounted seat belt as the shear force is applied directly where the bolt enters the threads, however, with an eye bolt the shear forces, I imagine, would be far greater.