Re: How does a torsionbar work?

[Jan van de Wouw <Jan@xxxx>]

"Thomas B" <tjb229@xxxx> wrote:

> I am a little embarrassed to ask this: How does the torsion bar 
> work in the door of the Delorean anyway?

To put it very, very simple, 
a torsion bar is a spring that winds and unwinds along its' own axis.

You can best compare it with a very tightly wound up rubber band:
take a rubber band and two pencils (or something similar),
now hold both pencils slichtly apart and put the rubber band
over both pencils. Turn the pencils oposite to each other,
along the axis of the rubberband so you het an "H"-shape, 
where the rubberband is the bar.

As you twist along you'll notice the twisting getting more and more 
difficult because of the torsion on the rubberband.
Now lay bot pencils flat and hold one down, the other one wil flip up 
and try to unwind the rubber band.

If you imagine the held pencil being the rear edge of the 
door/roof-opening above the rear window and the one trying to
flip up as the roof-part of your door you'll se how this works.

When the Bar "untwists" the force it delivers gets less graduately,
that's what the strut is for: as the Torsion-force gets less,
the strut gets leverage on the door ands helps the door up the last 
part of its' upward motion. That's also why you get "drooping"
doors when the struts wear out; there's no power in them to help
the doors up to its' full opening.

Another thing that this can explain is why there's so much danger
in adjusting the Torsionbars: if you totally let go of the pencil 
that represents the door it starts flopping around.
You would'nt flop around, but you can probably imagine what could
happen if it were you on a breakerbar on the other end.
Remember that the doors weigh about 85kg (160LBS(?)) if I'm 
correct, imagine the force needed to get that up on such small 
leverage: the torsionbar-force is applied only inches from
the hinge-axis and the doors are allmost 3 feet long measured
from hinge to door-sill/bottom!!!

I've never tried adjusting the T-Bars and I'll never try 
without an experienced person helping me!!!

Quite a long post for something so simple ;-)

JAN van de Wouw
Thinking Different... Using a Mac...
Living the Dream... Driving a DeLorean...

#05141 "Dagger" since Sept. 2000

check out the Delorean-Files at:
http://www.deloreanfiles.nl/
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