Falling rate spring design
Falling rate spring design
(OP)
I have seen compression coil springs that are rising rate, where the number of active coils decreases as the spring is compressed.
Has anybody ever seen a compression spring with a falling rate? Thinking about this for a couple minutes, I'm not sure how/if it can be done. I know it can be accomplished by using linkages that produce a falling rate from a constant rate spring, etc. But, I would like to do this via spring only. Any ideas?
Has anybody ever seen a compression spring with a falling rate? Thinking about this for a couple minutes, I'm not sure how/if it can be done. I know it can be accomplished by using linkages that produce a falling rate from a constant rate spring, etc. But, I would like to do this via spring only. Any ideas?





RE: Falling rate spring design
RE: Falling rate spring design
I assume mountainous wants a falling rate with a rising force not with a falling force.
RE: Falling rate spring design
RE: Falling rate spring design
We often do it with jounce bumpers made of high density foam, through much the same effect as the Bellevilles, such that a short section buckles and then operates in bending.
Cheers
Greg Locock
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RE: Falling rate spring design
Mike Halloran
Pembroke Pines, FL, USA
RE: Falling rate spring design
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Some of the isolator products even have a negative rate.
RE: Falling rate spring design
RE: Falling rate spring design
If one of these designs is used, you will be limited on the load and deflection by your space constraints and material properties. In this case, what is your load desired (negative) rate? also, what are your space constraints?
RE: Falling rate spring design
RE: Falling rate spring design
RE: Falling rate spring design
I have designed a falling rate spring. It was a rotating shutter. I used a catalogue extension spring. As the shutter rotated open, the spring tension transitioned from tangential to the circle, to normal to the circle.
While the spring force increased as the shutter opened, the spring torque, which is what mattered, dropped.
This is mechanism design. Sketch stuff out. Do calculations. Try thinking backwards from your requirement.
RE: Falling rate spring design
It would be helpful to know the approximate force, deflection, space and size that you are after.