US Patent 7909049 Operating mechanism for umbrella

An operating mechanism used in an umbrella is disclosed to include a telescopic shaft, first and second screw nuts fixedly mounted in the telescopic shaft at different elevations, a third screw nut is fixedly mounted in the runner of the umbrella, a first screw rod threaded through the first screw nut, a second screw rod threaded through the second screw nut and axially slidably connected to and rotatable with the first screw rod, a third screw rod threaded through the third screw nut and axially slidably connected to and rotatable with the second screw rod, and a transmission mechanism connected to the first screw rod and operable to rotate the first screw rod.