Abstract: A chair support structure includes a base, a driving component, a first transmission component, a leg component, and a back component. The driving component can be connected to the base, the first transmission component is connected to the driving component. Both the leg component and the back component are connected to the first transmission component. The first transmission component can include a first transmission member. The first transmission member can include a first connection portion and a second connection portion, each of which has a first end and a second end opposite to each other. The first end of the first connection portion can be pivotally connected to the leg component. The second end of the first connection portion can be fixed to the second connection portion. An angle can be formed between the first connection portion and the second connection portion.

Abstract: A mechanical linkage structure for linking a chair and a seat, comprises a first link, a second link, and a third link respectively used as a driven link, a fourth link used as a driving link, a fifth link, a sixth link, and a seventh link respectively used as a driven link. The first link is pivotally connected to the second link and the third link, respectively; the second link is pivotally connected to the fourth link and the fifth link, respectively; the third link is pivotally connected to the fourth link, the fifth link, and the seventh link, respectively; the fifth link is pivotally connected to the sixth link; the sixth link is pivotally connected to the seventh link; the fourth link is driven to rotate the first link, the second link, the third link, the fifth link, the sixth link and the seventh link, to realize the unfolding or collapse of the mechanical linkage structure.

Abstract: A headrest device includes a support frame, a pillow plate, a first driving member and a first transmission member. The first transmission member includes a first transmission rod, two first connecting plates, and two elastic members. Each end of the first transmission rod is respectively provided with a first extending plate pivotally connected to the support frame with a first pivot. Each of the two first connecting plates is pivotally connected to the first extending plate with a second pivot. The headrest device has a first rotating process when there is no obstruction in its path, in which the first transmission member rotates about the first pivot relative to the support frame to tilt the pillow plate, and a second rotating process when there is an obstruction, in which the pillow plate and the two first connecting plate rotate about a second pivot relative to the first extending plate.