Torsion springs used in the reverse direction 2

[jackpot]

Does anyone have any experience on using torsion springs in the reverse direction. I know that it is not adviseable to do so, but are there any rules / formulas that apply to this type of operation?

Thanks, Jack

 

[boldfish]

Not sure what you mean by reverse direction. I've created designs that utilize torsion springs in both the winding and unwinding directions depending upon the characteristics I was trying to exploit.

 

[desertfox]

Hi jackpot

According to the "Spring Design Handbook" by Associated Srings:- Torsion Springs should be operated in a direction
such that the body diameter tends to reduce in
size. This is because the residual stresses due to
forming are favourable when the spring is loaded in
this manner.The converse of this is true if the
spring is operated in such a manner that the body
diameter increases.
With this latter case it is advised that the
springs are stress relieved.


regards

desertfox

 

[israelkk]

To add to desertfox, the stress concentration factor (Wahl factor) for torsion spring operated in a direction such that the body diameter tends to "increase" is higher than the the stress concentration factor (Wahl factor) for torsion spring operated in a direction such that the body diameter tends to "decrease". Therefore, a torsion spring that is loaded in both direction will be able to give lower torque than a torsion spring loaded only in one direction i.e. the direction that tends to decrease the body diameter.