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Question Seatbelt tensioner

Discussion in 'DIY peripherals' started by bob williams, Feb 2, 2020.

  1. bob williams

    bob williams OSW sfx100

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    So I saw somebody use a bungee cord attached to the seatbelts and fixed that to a solid frame so that the belts get extra tension while braking. I have tried to make a similar setup with a 2dof seat mover.
    Problem is that there is to much friction where the belts go trough the seat, and the effect of the bungee cord is not noticable.
    Are there people who have succesfully made this?
  2. noorbeast

    noorbeast VR Tassie Devil Staff Member Moderator Race Director

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    Perhaps try creating a roller mount where the belt passes through the seat, to reduce friction.
    • Like Like x 1
  3. Gadget999

    Gadget999 Well-Known Member

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    perhaps your bungee cord is too weak
  4. SeatTime

    SeatTime Well-Known Member

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    Tried a similar setup many moons ago. IMO in practice the rig does not move enough in that plane to tighten the belts to a suitable degree. It also can put allot of load on the rigs motors. For best results use active belts (separately servo motor driven).
  5. dododge

    dododge Active Member Gold Contributor

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    Example: I'm in the process of making a belt tensioner and placed a 2-inch diameter aluminum conveyor belt roller right behind the seat. It has built-in ball bearings and the belts move very easily.

    [​IMG]
    • Like Like x 4
  6. bob williams

    bob williams OSW sfx100

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    Through, scn5 are maybe to weak. That roller looks like a good solution! Thanks for the picture! How much is the sensation for g-force effect?
  7. Gadget999

    Gadget999 Well-Known Member

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    @SeatTime

    seatime sells a kit to provide belt tension - uses powerful servo motors
  8. bob williams

    bob williams OSW sfx100

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    Thanks I will have a look!
  9. dododge

    dododge Active Member Gold Contributor

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    In my case I'm still building it and haven't even turned it on yet. My initial design is probably too complicated, but I figured while I had everything torn apart I might as well go for it. So there's one motor performing a "surge" function attached to a large set of rollers, ropes, pulleys, and springs. I've feel like I've done more knot-tying in the past few weeks than when I was in the boy scouts :)

    [​IMG]

    I've even got it rigged to tension the lap belts at a lesser amount than the shoulder belts -- but I suspect they might be pinched too tight against the seat for them to move easily. I won't know for sure until I finally get the remaining parts in place and turn it on.

    [​IMG]
    • Creative Creative x 3
  10. bob williams

    bob williams OSW sfx100

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    Wow! :thumbs So you don’t have a seperate tensioning servo? What kind of actuator do you use for movement?
    Would be nice to see it in action when everything is good to go!
  11. dododge

    dododge Active Member Gold Contributor

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    I should clarify: this is a commercial simulator platform which originally came with seat base that tilts forward and backward to simulate surge. It also had a passive belt tensioner where the belts were attached to the frame with springs, so when the seat tilted forward to simulate braking the belts would get tighter as a side-effect.

    As part of reworking it to a formula design, I had to make a lot of changes to the seat mounting including removing that tilting seat base. But the motor is still there and still programmed to simulate surge, so my idea is to have it operate the belts directly. That way I still get a tensioning effect even if the seat no longer tilts forward. Unfortunately this means the belts are now the only surge effect, but I can probably get by with that for the time being since the platform still has heave, sway, and traction loss.

    The surge actuator is a worm-drive motor mounted underneath, with a linkage that reaches up through the base of the platform. One of my rollers is on a hinged arm that is in pretty much the exact same position as the original tilting seat platform, so the linkage will still move the same way as before. If this all works as expected, for example when braking the roller will get pushed upward by the motor and tighten the belt ropes.

    [​IMG]

    When accelerating the roller will move down and the belts will loosen, so some of the extra ropes and pulleys are there to lightly pre-tension the system and take up any slack. I need to make sure the pulleys don't get so loose that they bang into the frame, and that none of the ropes ever get loose enough that they might get caught in some other moving part.
  12. bob williams

    bob williams OSW sfx100

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    Thanks for the explanation and pictures. Nice to see it in a video once it is completed!
    • Agree Agree x 1