PURPOSE: To protect a transparent panel, and to improve strength and an assembling characteristic by prenstalling a support in the lower side part of the transparent panel of at least the landing in/out port part among the transparent panel.

CONSTITUTION: A support stand 10 fixed to a main body frame 8 is arranged on this so that a support stand 14 having the plane part 14a and the vertical part 14b forming a screw hole 14A is installed on this support stand. Notches 16a are arranged in a plurality in the lower side part of a glass panel 16 to be adhered or fitted in a groove 15a of a support 15 by an adhesive G composed of an epoxy resin and a soft rubber material so as to integrally form the glass panel 16 and the support 15. At assembling time, a bolt 17 penetrating in the horizontal direction outward from the inside through a support 14 is screwed in the screw hole 14A to be firmly fixed. In this case, the glass panel 16 and a support 15 are integrally handled up to a completion of assembly from transport so as to play a role to protect the glass panel 16 at assembling time.