Garage springs - Any engineers perspective?

[CubbaCudet]

I'm looking at my garage door extension springs and I got to wondering:

Google says:
The force required to extend an extension spring is proportional to the distance it's stretched.

So.. looking at the attached picture, how does all that force being exerted on the spring while stretched not snap the tiny little area of metal in the circle?

Coming from a layman's term that a chain is only as strong as its weakest link, I find it incredible that such a small area (as compared to the entire spring) can sustain the forces applied to it without breaking.

Does this mean that the area in the circle is 'feeling' the same forces applied to the spring further down?

In your experiance, is the circled area typically the first place to break?

[RLause]

I think that is probably the first and only place they break. When mine broke, I fashioned some thin brackets shaped like an inverted W that I threaded into the end of the spring. They have been working that way for a looong time.

[garydee]

Here is something along the lines of the "W" metal piece to attach the springs to the mounting brackets. Hope the pictures can show this...

The first picture shows up the best. Looks like just some 5/8" x 1/8" flat stock wrapped around the ends of the coils to fasten it. Came this way from the factory. Might be hard to get these pieces in on large springs.

My springs are pretty heavy duty for a wood door that weighs over 500 pounds! As I recall, it wasn't easy to replace the springs even when I was younger!