Thus, there has been disclosed an improved safety liner for lenses that greatly reduces lens stress and which allows for irregularities in the contacting surfaces of a lens and a metal frame without damaging the lens. This is accomplished without altering the frame, while still allowing the lens to be easily mounted in the frame or removed therefrom while significantly improving the overall safety of the eyeglasses. Furthermore, the liner can be used to modify the diameter of the lens so that it will fit a frame that otherwise might be too large, thereby reducing manufacturing spoilage. Although the present invention has been described in terms of preferred embodiments, it will be apparent that numerous variations may be made without departing from the true spirit and scope thereof, as defined in the following claims:
To assemble a lens in a frame, the lens is edged following the geometric pattern of the frame rim, using a nonbeveled, or rimless, abrasive edging wheel so that after edging the lens can be passed through the closed frame. The rimless, or nonbeveled edge is illustrated at 68 in FIGS. 5 and 7, and at any given diameter is the same size, or slightly smaller, than the corresponding dimension of the rim. Using a standard grooving machine a circumferentially extending narrow groove such as that illustrated at 66 is cut in the peripheral edge 68 approximately 0.55 mm deep all the way around the circumference of the previously edged lens. The safety lens liner 51 (or 52) is then elastically stretched and positioned on the peripheral wall 68 of the lens with the inwardly extending tongue 62 (or 74) extending into the groove formed in the lens. At this point, the rimless-edged lens is effectively transformed into a lens having a shaped edge which can then engage the correspondingly-shaped groove formed in the rim 14. In the case of the embodiment of FIG. 5, the outer walls 54 and 55 provide a triangular, or beveled, outer surface, which in the embodiment of FIG. 7, the liner provides a rectangular outer surface which engages a correspondingly-shaped rectangular groove in rim 14. The lens may then be positioned in the rim 14 and the rim closed by means of the usual screw tensioning. If desired, a cyanoacrylate adhesive, or equivalent adhesive, may be placed between the liner and the lens to produce improved lens-to-frame retention and an improved index matching between the liner and the lens.
If you own a waterbed that has foam sides and looks like a regular mattress, then this is the place to find safety liners for the softside style of waterbed. If the safety liner inside that protects the base and foam rails needs to be replaced all you have to do is measure the inside depth of your foam side rails.
The lens 28 illustrated in the drawings is a composite lens; however, it will be evident that both all plastic and all glass lenses may also be shaped at their peripheral edges to receive the safety liner of the present invention so that the lens can be secured in a metal frame with a significantly reduced tendency to chip and fracture. Furthermore, glass and plastic lenses may be edged with nonbeveled, grooved peripheral edges as illustrated to receive liners for diameter adjustment to permit a lens that would normally be considered undersize to fit into a frame rim of either metal or plastic. Thus the liner can serve as an extension of the lens to increase the lens radius by the thickness of the liner. The tongue provided in the embodiments of FIGS. 5 and 7 provides a tongue and groove connection between the liner and the lens to secure the liner in a lateral direction (as viewed in FIGS. 5 and 7) so that it will remain on, and aligned with, the lens. This not only holds the liner in place when the lens is curved in three dimensions, so as to facilitate mounting of the lens in the frame, but also helps to retain the lens in the rim even under impact. Normally, the combination of the groove in the rim and the groove in the lens with the liner shaped as in FIGS. 5 or 7 will enable the liner to secure the lens in the frame; however, if desired, an adhesive may be used between the liner and the lens to hold the liner firmly in place.
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