RckyMtnTJ wrote:
The frame runs directly under the seat. Thinking about welding a plate to the frame that the bolt will go through. Probably going to get a professional to actually do the install. I might go see what the dealer wants for the frame. I assume since they can be found in the newer units, I may be able to find one prefabbed. Then again that might cost as much if not more than having a welding shop build it for me and install it. Another option would be to drill through and go through a plate (glorified huge washer) maybe 6"x6". My wife talked to the authorities and was told what gauge of metal and such was required.
Take a look at how seatbelts are fastened in most cars and trucks.
It's the secondary impact rather than the initial impact that causes injuries. Seatbelts are designed to prevent that secondary impact by keeping occupants secure following the initial impact.
Like helmets, seatbelts cannot prevent injury ... they serve primarily to reduce injury severity in an accident. Both do best in low-speed impacts - at higher speeds, they should use the same principle used in race car design ... absorb energy through sacrificial disintegration.
Using that principle, it's be okay for the seatbelts to "rip loose' in a high speed crash, as long as they slow the occupants significantly before letting go.
The force required to rip a 1/2" bolt, backed by a large diameter washer, through a piece of 3/4" plywood is very significant. Your 6" x 6" backing plate should be more than ample for the task.
BTW - most of the steel in light and medium duty truck frames is 3/16" thick ... the only place I'm using 1/4" steel is in the body brackets and that's only because the Energy Suspension universal mounts are designed for 1/4" thick material. (It's easier to use 1/4" stock rather than shim up for thinner stock.)
