I visited https://en.wikipedia.org/wiki/Linear_actuator which describes and pictures some linear actuators. They use a screw to convert between linear and rotational force, and they are in media drives of computers.
I also happen to have a DC motor that is geared for low. When a DC motor is forcefully turned, it becomes a generator with opposite gearing. So I might be able to try to make some kind of hijinxed form of this if I took apart a dvd drive for its tiny linear screw!
