On Fri, 22 Aug 2014 18:43:06 -0400, Ned Simmons
wrote:

On Fri, 22 Aug 2014 18:19:57 -0400, Meanie
wrote:

O

If you're pulling on it where you say "Fig 2", and it's pulling on
something where you say "Fig 1", then between the 210 degree bends it's
going to be all floppy, no matter what. You're putting a bending stress
on it that's strongest at your "Fig 2" point, and flat strap just doesn't
resist bending well. If you could substitute bigger material (tubing or
bar) for the cross piece up to the bend, and just use thin strap to the
ends, then you'd be a lot better.


You're dead on. The "fig 2" is where an adapter/mount is attached for a
very small trailer. The "fig 1" is where the drawbar attaches to an
axle. After my test run, the area in "fig 2" is bending inward, most
likely from inertia when braking, but overall, I realize the stop and go
will apply the most pressure in that area and soon break.

When you say bigger material, are you indicating an aluminum channel or
rectangular tube will work much better? This is my thought due to the
supporting sides/legs which I am hoping will eliminate the flexing and
strengthen that "fig 2" area.

Thank you

Making the frame as close to a triangle as possible (in other words,
reducing the 5-1/2" & 8" dimensions) will increase the stiffness.
Assuming the loads are all in the plane of the drawing, laying the bar
flat will make the frame *much* stiffer; 64x if I did the mental
arithmetic right. And switching to steel will make it 3x stiffer (and
3x heavier).
Would be a lot easier if we knew what this contraption is supposed to
do, and what it is supposes to attach to. I finally got the diagram to
open.

I'm assuming the two ends (diagram 1) are drilled and an
axle/pivot/pin runs through it and the framework you are building is
somehow supported at the "rear" (diagram 2) to keep it from dropping,
and there is a pivot(ball or pin) connecting it to the drawbar of
theis "lightweight trailer".

If it doesn't pivot at "diagram 1) and is not supported at "diagram 2"
you have a lot of other problems. What fits inside the frame that
requires it to be that shape??? If anything??.

We REALLY need more information to give you any kind of usefull
input.