Variable force wheel with limiting protection function and activation coal feeder

The variable force wheel capable of being limited and protected comprises a force wheel spring, a piston and a limiting stopper, the piston is connected to the lower end of the force wheel spring, and the limiting stopper is connected to the lower end of the piston; the center of the limiting stopper and the center of the piston coincide in the vertical direction, and when the activation coal feeder is in the maximum output state and has no load, the lower end of the limiting stopper abuts against the bottom of the air cylinder, so that the force wheel spring is prevented from being in the ultimate stretching state. As the center of the lower end of the piston is connected with the limiter, when the activation coal feeder is in a maximum output state and has no load, as the bearing capacity of the activation coal feeder is reduced and the elongation of the force wheel spring is increased, when the elongation of the force wheel spring is increased to a certain value, the lower end of the limiter is propped aga