Patent ID: 7726377

Claim:
A screen device comprising: a first screen installation frame; a second screen installation frame moveable between an opened state and a closed state, said second screen installation frame including an upper end section; a screen disposed between said first screen installation frame and said second screen installation frame; and a first upper guide frame including a guide rail projection; wherein said second screen installation frame includes a fall-down prevention guide section formed as a projection or a groove at said upper end section, said fall-down prevention guide section being disposed in said first upper guide frame, wherein said fall-down prevention guide section is disposed above said guide rail projection with a clearance between said fall-down prevention guide section and said guide rail when said second screen installation frame is in a normal state, wherein said fall-down prevention guide section is integrally included with said upper end section of said second screen installation frame, and wherein said fall-down prevention guide section is operable to contact said guide rail projection when the second screen installation frame is inclined away from said normal state so as to prevent said second screen installation frame from being detached from said first upper guide frame, wherein said second screen installation frame is supported such that said fall-down prevention guide section does not contact said guide rail projection unless said second screen installation frame is inclined away from said normal state, and such that said clearance is eliminated when said fall-down prevention guide section contacts said guide rail projection.