Patent ID: 7637607

Claim:
A shelter frame for detachably mounting in front of a primary frame which comprises two lenses and a bridge extending between said lenses, wherein said shelter frame comprises: two spaced apart shelter lenses defining a control distance between two inner sides of said shelter lenses; two lens holders provided at two outer sides of said shelter lenses respectively; and a retractable arm extended between said two inner sides of said shelter lenses for applying a retractable force therebetween to adjust said control distance, wherein when said shelter lenses are pulled away from each other to lengthen said retractable arm for extending said control distance, said lens holders are adapted for engaging with two outer sides of said lenses of said primary frame, such that when said retractable arm is retracted via said retractable force, said shelter lenses are adapted for holding in front of said lenses respectively, wherein said retractable arm comprises a first member mounted to said inner side of one of said shelter lenses, a second member mounted to said inner side of another said shelter lens, and a retraction unit coupling between said first and second members such that said shelter lenses are adapted to be pulled away from each other to extend said control distance, wherein said retraction unit comprises an elongated control arm having an affixing end portion affixed to said second member and a sliding end portion slidably coupled with said first member, and a resilient element coupling with said sliding end portion of said control arm for applying said retractable force against said first member to pull said first member towards said second member, wherein said first member comprises a tubular sleeve having a closed end mounting to said inner side of said respective shelter lens and an opened end extended towards said inner side of another said shelter lens, wherein said sliding end portion of said control arm is slidably received in said tubular sleeve to slidably engage said second member with said first member, wherein said first member further comprises a front covering panel sidewardly extended from said opened end of said tubular sleeve to cover a front side of said second member when said first and second members are coupled end-to-end.