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H. L. Chauvin · 05-11-2012, 01:28 AM

Maybe something to think about prior to designing seat belt anchorage:

About 2 years ago, at night, I saw a car that did not stop at a very rural intersection & crossed the highway with brakes applied, flipped upside down, & dropped down about 8 feet into a large continuus, soft earth swale, with the car's 4 wheels in the air. My wife called 911 before approaching the accident.

Passenger & driver were both swinging & "suspended", facing downwards, & moaning. Appeared neither could unlatch their seatbelts because of the tension on their seat belts latches caused by the 200 pound weights of each of their bodies. (Took several firemen to support one suspended body at a time to free the seat belts -- one seatbelt unlatched, one cut with knife).

Theoretically, after the crash, each of the seat belt bolts on the out-side was carrying one-half of the person's 200 pound suspended weight, or 100 pounds.

On some Model A seat belt diagrams, one (1) in-side center bolt is indicated for attaching both in-side halves of both seat belts; hence, in this scenario, "after the crash", this center bolt would have to carry a concentrated suspended load of 100 x 2 = 200 pounds.

At times, center bolt attachment & anchorage may be indicated as a 12 gage x 2" strap, or maybe a 1/4" x 2" steel strap, or something else.

This example below is definitely not at all the worse case scenario for a live load impact in an accident, but on any Model A body, wood or lightgage steel, try to imagine first removing the front seats & back seats.

Next, somewhat "similar" to the above accident, allow a 200 pound person to jump off of an 8 foot high step ladder & land in the "center" of a Model A undercarriage, immediately behind a Model A front seat or rear seat.

Try to picture what would happen to a 1/4" thick x 2" wide steel flat bar spanning 40" & attached to a lightgage floor pan or lightgage body channel with a 200 pound weight dropped from 8 feet.

Hopes this helps just a little for one to begin to decide how to securely anchor all of one's Model A seat belt bolts.

05-11-2012, 01:28 AM	#5
H. L. Chauvin Senior Member Join Date: May 2010 Posts: 4,179	Re: Seat belts for Fordor Maybe something to think about prior to designing seat belt anchorage: About 2 years ago, at night, I saw a car that did not stop at a very rural intersection & crossed the highway with brakes applied, flipped upside down, & dropped down about 8 feet into a large continuus, soft earth swale, with the car's 4 wheels in the air. My wife called 911 before approaching the accident. Passenger & driver were both swinging & "suspended", facing downwards, & moaning. Appeared neither could unlatch their seatbelts because of the tension on their seat belts latches caused by the 200 pound weights of each of their bodies. (Took several firemen to support one suspended body at a time to free the seat belts -- one seatbelt unlatched, one cut with knife). Theoretically, after the crash, each of the seat belt bolts on the out-side was carrying one-half of the person's 200 pound suspended weight, or 100 pounds. On some Model A seat belt diagrams, one (1) in-side center bolt is indicated for attaching both in-side halves of both seat belts; hence, in this scenario, "after the crash", this center bolt would have to carry a concentrated suspended load of 100 x 2 = 200 pounds. At times, center bolt attachment & anchorage may be indicated as a 12 gage x 2" strap, or maybe a 1/4" x 2" steel strap, or something else. This example below is definitely not at all the worse case scenario for a live load impact in an accident, but on any Model A body, wood or lightgage steel, try to imagine first removing the front seats & back seats. Next, somewhat "similar" to the above accident, allow a 200 pound person to jump off of an 8 foot high step ladder & land in the "center" of a Model A undercarriage, immediately behind a Model A front seat or rear seat. Try to picture what would happen to a 1/4" thick x 2" wide steel flat bar spanning 40" & attached to a lightgage floor pan or lightgage body channel with a 200 pound weight dropped from 8 feet. Hopes this helps just a little for one to begin to decide how to securely anchor all of one's Model A seat belt bolts.