METHOD OF MOUNTING A MAGNIFYING ATTACHMENT ON A SPECTACLE LENS

1,098,735. Magnifying attachments for spectacles. C.H. KEELER. Aug.24, 1966 [Jan.26, 1966], No.3537/66. Heading G2J. A pair of spectacles have a magnifying attachment 14 attached to at least one lens 12 thereof by means of a metal or plastics sleeve 13, one end 15 of which is cemented into a circular groove 16 in the surface of the lens. The end 15 of the sleeve 13 may be in a plane 17 parallel to the general plane 18 of the lens 12, but may be inclined to the body of the sleeve 13 such that the optical axes of the magnifying attachments 14 on both lenses meet at a point of focus. The magnifying attachment 14 may be a telescope unit or a single glass or plastics lens, which may be screwed into the sleeve 13. The sleeve 13 may be mounted by temporarily securing a disc to the rear side of the lens concentric with the optical centre thereof (dependant on pupillary distance of the user), mounting the lens rear side down in a jig, Figs. 5-6 (not shown), cutting the groove 16 with a trepanning tool mounted on a vertical spindle concentric with the disc, removing the disc and cementing the sleeve 13 into the groove. The orientation of the sleeves 13 may be checked by mounting a pointer, Fig. 7 (not shown), of the required length, in each sleeve and manipulating the spectacle frame until the ends of the pointers meet at the point of focus.