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Kevin in NJ · 10-24-2016, 08:18 AM

You have a difficult task ahead of you.

The A from an accident standpoint will always not be a modern car.

My thoughts are you may not really want to have 3 point as you have not good way to anchor the top point. You need to have the point kind of far back because the only way to get strength is to make the system in shear. The B pillar is right at you shoulder and is somewhat weak unless you re-engineer a metal cage instead of the wood.

** I forgot about slant window bodies, they have steel posts and would be a different design thought.

Why is this bad, well the 3 belt system is only as good at all the mount points. The shoulder point is going to be fairly weak (think able to hold over 1000 lbs in the direction the belt will pull). Once the shoulder rips you loose waist belt.

So a basic waist belt system can be rigged in shear that will handle a lot of the force and not break. That will hold you in place. It may not be pretty in the fordor to do correct. Too many belt systems I have seen made up for the A's have the belts going directly down from the back of the seat cushion. This is not good as it will not hold a lot and there is a looseness due to the cushions allowing the belts to move a lot till they are taught. People also use the wrong metals and do not put everything in shear, that is 90 degrees to the bolts to use the strength of the bolts. Model your belts on how they did them in the 60 and 70's cars. The Mustangs are a good teaching model.

Now lets move to the cab. The area where you sit is just too close to everything. It does not take much till you are going to hit something that will hurt you. Yes, your head will leave a nice dent in the dash board. Yes that steering wheel is strong and will hurt. If you can get enough time because of a lap belt the injury level decreases quite a bit.

I will leave you with the idea these are just my opinions. I have a degree in physics, I ran in a rescue squad for 14 years and I have some idea about materials strength. I am not a mechanical engineer so use at your own risk.

10-24-2016, 08:18 AM	#3
Kevin in NJ Senior Member Join Date: May 2010 Location: South East NJ Posts: 3,398	Re: 3 point seat belts in Fordor car You have a difficult task ahead of you. The A from an accident standpoint will always not be a modern car. My thoughts are you may not really want to have 3 point as you have not good way to anchor the top point. You need to have the point kind of far back because the only way to get strength is to make the system in shear. The B pillar is right at you shoulder and is somewhat weak unless you re-engineer a metal cage instead of the wood. ** I forgot about slant window bodies, they have steel posts and would be a different design thought. Why is this bad, well the 3 belt system is only as good at all the mount points. The shoulder point is going to be fairly weak (think able to hold over 1000 lbs in the direction the belt will pull). Once the shoulder rips you loose waist belt. So a basic waist belt system can be rigged in shear that will handle a lot of the force and not break. That will hold you in place. It may not be pretty in the fordor to do correct. Too many belt systems I have seen made up for the A's have the belts going directly down from the back of the seat cushion. This is not good as it will not hold a lot and there is a looseness due to the cushions allowing the belts to move a lot till they are taught. People also use the wrong metals and do not put everything in shear, that is 90 degrees to the bolts to use the strength of the bolts. Model your belts on how they did them in the 60 and 70's cars. The Mustangs are a good teaching model. Now lets move to the cab. The area where you sit is just too close to everything. It does not take much till you are going to hit something that will hurt you. Yes, your head will leave a nice dent in the dash board. Yes that steering wheel is strong and will hurt. If you can get enough time because of a lap belt the injury level decreases quite a bit. I will leave you with the idea these are just my opinions. I have a degree in physics, I ran in a rescue squad for 14 years and I have some idea about materials strength. I am not a mechanical engineer so use at your own risk. Last edited by Kevin in NJ; 10-24-2016 at 10:14 AM.