19 May 1999
So how does one attach a body to this heaving
platform we call a chassis. I guess there's a thousand ways and
I also guess I chose one of the more complex and expensive ones
but here goes.
We've already determined that the body should
be mounted at three points, but those points still have to flex
a little, you can't just weld the body onto the chassis. There's
also the question of vibration from the road, it would be nice
to reduce this as well.
My first thought was air bags, why not mount
the entire body on three air bags? Well the answer to this question
is "cost and complexity". I spent quite a lot of time
designing an air bag system before I decided that it was getting
too complicated. As the air bags have no lateral stability a lot
of torsion bars and levellers are needed. It all got too much
and probably beyond my engineering ability.
Next I started looking for rubber mounts. I
found a few options and settled on some rubber "donuts"
made in England (available from Shock & Vibration Technologies
in NSW). These mounts are designed for off road equipment and
large trucks. Sounds just right.
The mounts come as two rubber pieces that clamp
either side of a steel donut, see below.
||The three pieces as supplied.
||And clamped together.
The steel part is supplied by SVT because
the shape and dimensions of the hole are important. This lot is
designed to be used something like the following.
My version looks like the drawing below. We'll
cover the front body mounts first then look at the rear mounts
in a later diary entry.