Low strength belleville washers

Check with these folks:

They offer bellevilles with slots cut into the ID to reduce spring rate. I've only noticed them in their literature when purchasing other disc springs from them, so I'm not sure if they're a standard product or not.

I have used their serrated bellevilles, which are sized to fit under the heads of socket cap screws and are thinner than typical, so might be worth a look as well.

Ned Simmons

You can put the washers in series to reduce their effective spring rate. You put them on alternating up and down.

Jim

jim rozen wrote in news: snipped-for-privacy@drn.newsguy.com:

The rate/distance will decrease, as you are increasing the max distance of travel allowed. Or to look at it differently, when you make space and double the springs this way, and keep your initial compression distance the same, you cut the actual compressed distance of one spring in half.

For a comprehensive selection of belville springs, and any other spring you can imagine, look at these guys:

Good folks to deal with.

Lacking a source for the particular thrust you need, you might anneal some spring stock, "coin" your own washers, then re-temper them. It's not as difficult nor time-consuming as it sounds.

Surprisingly, most hardware stores sell very thin spring washers in both wave and Belville styles. If the thrust (or travel) of the thin washer is not sufficient, you can stack them (in parallel, or all stacked the same way) to increase thrust, or in series (face to face and back to back) to increase travel.

LLoyd