3 point seatbelt in the middle

Discussion in 'Mech Tech' started by bluething, Dec 3, 2013.

  1. has anyone ever put one in the front of their bus?? Ive got a Crewcab with the bulkhead between the front and back seats. and wondered if anyone has fitted a seatbelt to the middle seat. the anchor points are fine as they are just where the lap belt fits but I'm wondering where the reel would fit or if they used the adjustable strap type belt.

    I'm rambling now....

    Cheers
    dave
     
  2. I have crewcab and bus both with front bench seats. Both have lap belts. Lap belts are a safer option than attempting to install a 3 point belt.

    I've been involved in a research test project years ago following the M4 minibus tragedy and I could type for hours why its a bad idea to try and retro fit a 3 point belt in this area, but in brief;

    1) you need a very strong anchor point, the bulkhead doesn't provide this
    2) you won't be able to get the reel high enough, therefore in a collision you'll likely rip the passengers arm off at the shoulder and/or break their back/spine. At best.

    I could go on.

    Sit tight though as there will be loads of people along shortly singing the virtues of doing this and/or explaining why cars were much safer back when seatbelts didn't exist and everyone sat on wooden benches...
    :)
     
    bluething likes this.
  3. I know what you mean now, I used to have a small roll bar fitted in a landrover softop that put the top corner anchor point above the shoulder, dont think i fancy that much in fairnes, espacialy without head rests....

    Cheers Joker, think i'll stick with the lap belt.... maybe make lesser freinds sit in the middle :D
     
  4. Don't say that? Our youngest sits in the middle!!!

    The point being the anchor point needs to be above the shoulder height, not below shoulder height so sounds like your landy was correct. Assuming the roll bar was up to it :)

    Think of the forces applied in a front end prang, with the belt anchor above shoulder height the forces are transferred into the chassis above the shoulder, so the belt acts as a barrier which your body presses against. If the anchor point is behind and below your shoulder height the impact forces are transferred directly into your body until the seatbelt pulls tight. In an old style seatbelt without any form of pretensioner that is a lot of movement. If it were someone my height it would be almost a foot, and the belt would try to pull itself right against the next strongest thing which would be the top of the bulkhead. The seatbelt would slice straight through any bone and soft tissue above the top line of the bulkhead, therefore about to the middle of the torso.

    Look here and go to 8 minutes 30 seconds which will give you some idea of what a passengers injuries would look like



    Doesn't bear thinking about the consequences of that.
    :)
     
    Last edited: Dec 3, 2013
  5. so provided that my passenger is made out of mimetic poly-alloy (liquid metal) then they should survive. cool! I'll do that

    Get to the CHAPPAAA!
     

Share This Page