PURPOSE: To rotate a rotated material by 180° without forming a wasteful space.

CONSTITUTION: A slide groove section 22A is formed on the base end side of a stay material 22 so that the stay material 22 can be relatively moved while the coupling piece 20A of the first bracket 20 is coupled. A connecting pin 28 penetrating the stay material 22 is coupled with the second bracket 26. A slider 32 is arranged to face the stay material 22, and the slider 32 and the first bracket 20 are connected by links 42, 44. A hook pawl 32B and a coupling pawl are formed on the slider 32, and the coupling pawl and the coupling piece 20A are coupled with the slide groove section 22A. Connecting plates 34, 36 are supported by the hook pawl 32B, and a support pin 38 erected on the connecting plates 34, 36 is hooked on the second bracket 26. A link 46 is arranged between the middle of the link 42 and the side face of the stay material 22.