US Patent 7637607 Shelter frame for spectacles

A shelter frame includes two shelter lenses, two lens holders provided at two outer sides of the shelter lenses respectively, and a retractable arm extended between two inner sides of the shelter for applying a retractable force therebetween to adjust the control distance. When the shelter lenses are pulled away from each other to lengthen the retractable arm for extending the control distance, the lens holders are adapted for engaging with two outer sides of the lenses of the primary frame, such that when the retractable arm is retracted via the retractable force, the shelter lenses are adapted for holding in front of the lenses respectively so as to detachably couple the shelter frame in front of the primary frame.