Looking for a way to convert rotary motion to linear, but it should take less energy to get back to initial position than when going from initial position to the end position.
Specifically, a screw mechanism pushes a spring with multiple of full motor rotations. Then it stays in this ending position for a while as screw prevents the spring from pushing the mechanism back. Now, I'm looking for a mechanism that will retract back to the initial position with less work than before, f.i. with a single motor turn in the same or opposite direction.
For example a lipstick mechanism works with a cam and a pin. Imagine that this mechanism pushes a spring and you can draw the pin out of the cam so the spring will push back. The problem is how to do that with a single rotational motor.