three point belts

L

lefty rodan

Member
Hi again:
I'm open to suggestions/advice on how to go about installing three point seat belts in my 50 merc coupe. Anyone done this? Safety trumps originality for me. Thanks for your help.
Lefty Rodan
 
I restored a set of genuine vintage Rotunda lap belts for my Lincoln. I used heavy eye bolts and large washers in the floor. I suppose you could attach a shoulder belt to the B piller somehow.
Julianos may have something. Maybe use a set up out of a newer car or truck.
 
Try "Seatbelts Plus". If you have at least 2" between seat and door panel and can attach
one part of belt between door lace and window frame it will work. Give them a call
and they may can offer suggestions. Charles
 
Got lucky with my '47 Coupe. After using my wife as a "dummy" to figure where to position the two sets of thru-floor bolts, I checked underneath the floor FIRST then drilled the floor panel and installed the reinforced floor units. Then to the shoulder harness anchor for the upper door pillar. Removed rear window garnish and the vertical upholstery strip between the door edge and the rear window body frame. Found is a 3/4 inch gap between the two body flanges there. The belts were furnished with a 3/4 inch anchor bolt and a 1 inch by 2.5 inch threaded reinforcing plate/washer. Stuffed a rag in the lower portion of the pillar space to catch any parts accidentally dropped. Selected desired mounting height and then worked the threaded plate into the pillar space temporarily holding it in-place with my small finger. I had cut a 3/4 inch hole in the upholstery panel at that location and put a large shiny flat washer on the belt anchor bolt. Threaded the anchor bolt with washer and panel into the plate inside the pillar. Replaced rear window garnish. The resulting shoulder-belt anchor is not welded in-place and may not equal a modern car belt anchoring detail but there's certainly no way I can pull it loose. My 3-point belts are NOT retractable and lay flat when unused so they don't greatly interfer with people entering or leaving the back seat.
 
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Drbrown said:
...may not equal a modern car belt anchoring detail but there's certainly no way I can pull it loose.
Click to expand...

Keep in mind that there's quite a bit more force acting on the retainer in an accident than what you'd ever be able to apply yourself without some sort of mechanical advantage.

I could easily see your anchor plate plate pulling through the gap you have it bridging, especially if it's only got a 1/8" x 2.5" bearing area on each side.
 
I too was concerned about the amount of force applied to the shoulder belt anchor during a crash. I know I'm getting "techie" here but this was my kitchen-table analysis .... because my car is a coupe, the door pillars holding the shoulder anchors are located well-back of the front seat/occupant location. The stress on the shoulder belt anchor and body frames is thus applied almost side-ways to the pillar, creating a twisting shear force on the car frame and anchors, rather than a tension pull-out force. As well, with the door in closed position next to the pillar (yes, one hopes it stays that way), the door assembly should reinforce the pillar while absorbing some of the crash impact.

Re the reinforcing plate position in the pillars, the plates are about 1/4 inch thick and I positioned them horizontally (rather than vertically) so there is about 1" x 1"inch grip area on/under each side of the body pillar frames. The large flat washers on the anchor bolts that cover the body flanges are abt 3/16" thick and 2.5" OD and are held in-place by a shoulder on the anchor bolt shaft .... contributing to the resistance of twisting stresses.

Needless to say, I hope my analysis is never tested.
 
I would think that anything that slowed down any part of your body prior to impact with the steering wheel or dash even if it was only momentary would be a benefit. I'm still trying to figure out a good way to add upper body restraint to the lap belts in my pickup.

Just my $0.02 worth.
 
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