The highlight is: the background technology is composed of a swing arm and a slider. There are chute on both sides of the swing arm, and a sliding pin is set in the chute. The sliding pin is set on a connecting plate. The block and the connecting plate are rotationally connected through another sliding pin. A mechanical arm with this kind of structure, the technical car sunroof is installed on the roof of the car, and usually includes a movable cover that can perform lifting, lowering or smoothing movements. Therefore, there is a need for a mechanism component that can be used to install and fix the skylight cover, and can also achieve lifting, lowering or smooth movement. The patent application number 200620048770.4 discloses a car sunroof movement mechanism, which includes: a sliding arm guide rail with a chute and a sliding plate.