Re: G0704 Power Draw Bar Belleville springs 3000# holding force?
Jeff,
CS900 explained it pretty clearly. Every time you stack a washer on a washer, coolie hat fashion, you get double the spring rate of a single washer. To increase the travel of the washer you stack them coolie hat opposed. You asked about our setup on the Grizz and I referred you to post #73. That shows two 2050lb washers in nested-inverted stack of 12. This gets us 2 X 2050 lbs = 4100 lbs and the nested-inverted stack gives us the travel we needed, .132. Getting the spring rate out of the stack is only part of the equation, you need to work the formula so you get the travel you need that allows you to load the washers up yet leaves enough travel for your air cylinder to release the tool holder.
The Grizz has a pretty tall stack, but the washers are big strong fatties that don't flatten out much meaning we needed 12 of them so their combined 'mash' allowed the tool holder to release. I think this is how it works?
Stuart
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