PURPOSE: To prevent a wall surface or the like from being damaged due to a lever shaft by forming a stopper part which is brought into contact with a fixing board and which restricts the rotation of the lever shaft in the lever shaft.

CONSTITUTION: A mobile board 9 is connected to a fixing board 8 having a heater so as to be freely rotatable and also the mobile board 9 is opened/closed as against the fixing board 8 by the lever shaft 10 which is fitted to the fixing board 8 so as to be freely rotatable. The stopper part 15 by which a part of the lever shaft 10 is abutted on the fixing board 8 and the rotation of the lever shaft 10 is restricted when the lever shaft 10 is rotated and operated to open the mobile board 9 is formed in the lever shaft 10. As a result, the rotation of the lever shaft is restricted by the stopper part even when an obstacle such as the wall surface is in the neighborhood of the equipment so that the wall surface or the like is not damaged by the lever shaft and also a mobile range is reduced. Then an operability is improved.