Why isn't the constraint I put on these two parts working?

I have two servo hinge constraints to act like a drawbridge is going down. The constraints are facing the same way and the AngularSpeed = 0.3 and ServoMaxTorque = 10,000,000 because the model that is moving has a lot of parts. Here is the script that makes it move:

local hinge = script.Parent

while true do
	hinge.TargetAngle = -90
	wait(2)
	hinge.TargetAngle = 180
	wait(2)
end

This isn't making the bridge move and I don't know why. Please help me if you can and thanks in advance:).

~rilgundam