On Mon, 7 Mar 2005 18:41:35 -0800, "Pete Schaefer"
wrote:

into the system through a couple of springs, and if you're asking for
more force than what they deliver then you've already gone off the wrong
side of the page.

Putting springs also puts lag into your system. More tendency for
oscillatory behavior.

I am not sure what he has in mind, but I've found that using preloaded
(tight wound) springs, when the "inputs" are applied via them,
introduce only the additional mass. If they are not preloaded ... the
mathematics gets beyond me.

Example ... take an old style screen door spring (sounds redundant,
doesn't it g), cut it to a lenght of an inch (for example only), use
an anvil to pop out a turn, pull on it ... some reasonable force is
applied before the spring begins stretching (macro level coils
separating ...not counting the tiny bits of stretch in the ends)

I used a similar method with shear load cells to protect them; the
first 10 pounds was applied to the cell with "no" deflection. The
next 2 compressed a spring and applied load to the cell. After that,
I had metal-metal preventing further load on the cell. Keeps the 15
pound cell from being destroyed when a man stepped in the weigh
hopper.