Patent Publication Number: US-RE37523-E

Title: Eyeglasses having interchangeable lenses and attachment clips

Description:
TECHNICAL FIELD 
     This invention relates to eyeglasses, and more particularly, to eyeglasses having easily interchangeable lenses. 
     BACKGROUND OF THE INVENTION 
     There are presently a wide variety of eyewear styles, including sunglasses, that are commercially available. These sunglasses vary both in the style of the frame and the optical characteristics of the lenses mounted in the frame. The need for a wide variety of lens characteristics stems at least in part from the variety of circumstances under which sunglasses are used. For example, blue-tinted lenses are often considered superior for boating and other water-related activities. Neutral-density lenses are considered superior where it is undesirable for the sunglass lenses to change the perceived color of objects. Personal preference also plays a role in the variety of lens tints that are commercially available. Even for a given lens color, different degrees of optical density (i.e., “opaqueness”) are often desired, depending upon lighting conditions and personal preference. For example, a higher optical density may be desired for midday conditions, particularly in highly reflective environments such as snow, while a lower optical density may be preferred later in the day, particularly in less reflective environments. As a result, there is a need for a sunglass lens to have a wide variety of optical properties. 
     In the past, it has been difficult for users to select the optimal lens for the wide variety of conditions in which sunglasses are worn. Not only is there an often prohibitive expense in purchasing sunglasses for a variety of conditions, but there is also the inconvenience of carrying around different sunglasses for different conditions which may vary during a single day. For example, for a skier to have the optimum lens on a partly cloudy day, it would be necessary for the skier to carry at least two pairs of sunglasses having lenses with different optical densities. As a result of the costs and inconvenience of having different sunglasses available for different conditions, most sunglass wearers do not have the optimum lens much of the time. Instead, the sunglass wearer must compromise on a lens that, while not optimum for any lighting condition or activity, is at least somewhat satisfactory for all lighting conditions and activities. 
     It would be possible for sunglasses to have a wide variety of optical characteristics if the lenses could be easily and quickly removed from the sunglass frames. The wearer would then only need to purchase and carry a variety of lenses. A suitable selection of lenses would be far more compact and less expensive than a comparable selection of eyeglasses. However, lenses are preferably removed from conventional sunglass frames only by optical professionals. Furthermore, frequent removal and reinstallation of lenses in conventional sunglass frames tend to weaken the frictional connection between a lens and frame so that eventually the lens would become loose enough to fall out during strenuous activity. 
     As a result of the limitations of conventional sunglasses, there is a need for sunglasses that allow the optical properties of the sunglass lenses to be easily and quickly varied by the wearer in a convenient manner. 
     SUMMARY OF THE INVENTION 
     The inventive eyeglasses include a frame having a bridge interconnecting a pair of frame sections. Each frame section includes upper and lower frame members extending from the bridge to respective attachment areas. A pair of temples or other securing devices are attached to the attachment areas of respective frame sections. A lens is releasably held in place in each frame section by inner and outer lens attachment clips that extend along at least one of the frame members to retain the lens against the frame members. The inner lens attachment clip extends from the bridge part of the way toward the attachment area, and the outer lens attachment clip extends from the attachment area part of the way toward the bridge so that the inner and outer lens attachment clips are separated from each other by a gap. The frame or the lenses are fabricated from a resiliently compliant material so that the frame or lenses may be resiliently deformed to allow the lenses to be installed in and removed from respective fame sections. 
     The lens attachment clips preferably extend along outer surfaces of the frame members so that the lens attachment clips are visible along the outer surfaces of the lenses when the eyeglasses are being worn. The inner and outer lens attachment clip of each frame section may extend along either or both of the upper and lower frame members. Lenses may be installed and removed from the frame easily using a variety of techniques in which the lens is installed and removed from either of two directions. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     FIG. 1 is an isometric view of one embodiment of the inventive eyeglasses. 
     FIG. 2 is a partial cross-sectional view taken along the line  2 — 2  of FIG.  1 . 
     FIG. 3 is an isometric view of another embodiment of the inventive eyeglasses. 
     FIG. 4 is a schematic view showing one technique for installing a lens in a frame of the eyeglasses shown in FIG.  1 . 
     FIG. 5 is a schematic view showing one technique for removing a lens from a frame of the eyeglasses shown in FIG.  1 . 
     FIG. 6 is a schematic view showing another technique for installing a lens in a frame of the eyeglasses shown in FIG.  1 . 
     FIG. 7 is a schematic view showing another technique for removing a lens from a frame of the eyeglasses shown in FIG.  1 . 
    
    
     DETAIL DESCRIPTION OF THE INVENTION 
     One embodiment of the inventive eyeglasses is shown in FIG.  1 . The eyeglasses are embodied in sunglasses  10  having lenses  12 ,  14  mounted in a frame, generally indicated at  20 . The frame  20  includes two frame sections  22 ,  24  interconnected by a bridge  26 . Nose pads  28  project downwardly from the bridge  26  to comfortably support the frame  20  on the nose of a wearer. 
     Each frame section  22 ,  24  includes an upper frame member  30  and a lower frame member  32 , both of which extend from the bridge  26  to an attachment area  36 . A pair of temples  38  are pivotally secured to respective attachment areas  36  in a conventional manner. However, other securing devices, such as straps extending between the attachment areas  36  behind the head of the wearer, may be used. 
     The lens  12  is shown installed in the right frame section  22 , and the lens  14  is shown removed from the left frame section  24 . As is most apparent in the drawing of the left frame section  24  without the lens  14 , the frame section  24  includes an inner lens attachment clip  40  and an outer lens attachment clip  42 . The inner lens attachment clip  40  includes a leg  44  that extends upwardly along the upper frame member  30  and a leg  46  that extends downwardly along the lower frame member  32 . (It should be noted that the terms “upwardly,” “downwardly,” “front,” “rear,” and the like as used herein are with reference to the orientation of the eyeglasses as they are normally worn). The outer lens attachment clip  42  includes an upper leg  48  that extends upwardly along the upper frame member  30  and a lower leg  49  that extends downwardly along the lower frame member  32 . Since the lens attachment clips  40 ,  42  extend only part of the way toward each other, a gap is formed between the lens attachment clips  40 ,  42 . 
     With reference also to the cross-sectional view of FIG. 2, the clips  40 ,  42 , including their respective legs  44 ,  46   48 , and  49  are spaced from the forward surface of the upper and lower frame members  30 ,  32 . The spacing between the clips  40 ,  42  and the frame members  30 ,  32  is preferably slightly less than the thickness of the lens  14 . Since the frame  20  is preferably formed from a resilient material, such as resilient plastic, the lens resiliently deforms the clips  40 ,  42  and/or frame members  30 ,  32  to securely hold the lens  14  in position. As also shown in FIG. 2, the forward/rearward curvature of the upper and lower frame members  30 ,  32 , respectively, conforms to the forward/rearward curvature of the lens  14  so that the rear edges of the lens  14  are either in contact or closely adjacent the forward surfaces of the frame members  30 ,  32 . 
     Another embodiment of the inventive eyeglasses is illustrated in FIG.  3 . The eyeglass  50  shown in FIG. 3 is substantially identical to the eyeglass  10  shown in FIG. 1, and substantially identical components have therefore been given the same reference numerals. Furthermore, in the interest of brevity, an explanation of these substantially identical components will not be repeated. 
     The eyeglass  50  shown in FIG. 3 differ from the eyeglass  10  shown in FIG. 1 in the configuration of the outer lens attachment clip  52 . More specifically, the lens attachment clip  52  includes an upper leg  54  that extends a relatively long distance along the upper frame member  30 . Unlike the lens attachment clip  42  shown in FIG. 1, the lens attachment clip  52  does not include a downwardly extending leg. 
     A variety of techniques can be used to remove the lenses  12 ,  14  from the frame  20 , with the optimum technique depending upon the specific frame and lens structures and the preference of the user. As illustrated in FIG. 4, the lens  14  can be installed from the top of the frame  20  by placing the outer edge of the lens  14  beneath the outer lens attachment clip  42  and the lower inner edge of the lens  14  beneath the upper leg  44  of the inner lens attachment clip  40 . The user then exerts a force on the upper edge of the lens  14  in a downward direction (i.e., toward the lower frame member  32 ), thereby forcing the remainder of the inner edge of the lens  14  beneath the inner lens attachment clip  40 . As shown in FIG. 4, the force is preferably applied to the edge of the lens  14  at a location that is closer to the inner lens attachment clip  40  than it is to the outer lens attachment clip  42 . Under some circumstances, it may also be necessary to hold the lens  14  against the frame members  30 ,  32  while the lens is being pushed beneath the clip  40  to keep the lens between the clip  40  and the frame members  30 ,  32 . 
     The lens  14  can be removed from the frame  20  as shown in FIG.  5 . The user applies a force to the lower edge of the lens  14  adjacent the inner lens attachment clip  40 . Because of the resilient nature of the frame  20  and/or lens  14 , the lens  14  slides out from underneath the lens attachment clip  40 , thereby removing the lens  14  from the frame  20 . After removal of the lens  14 , another lens having different optical characteristics, such as tint or optical density, can be reinstalled in the frame  20  as shown in FIG.  4 . 
     In addition to installing the lens  14  from the top of the frame  20 , the lens  14  can also be installed from the bottom of the frame  20 , as illustrated in FIG.  6 . In fact, installation from the bottom is preferred for frames such as that illustrated in FIG. 3 having lens attachment clips  52  that are substantially more extensive along the upper frame member  30  than they are along the lower frame member  32 . As illustrated in FIG. 6, the inner edge of the lens  14  is placed beneath the inner lens attachment clip  40  and a force is applied to the lower edge of the lens  14  adjacent the outer lens attachment clip  52 . As before, it may be necessary to hold the lens  14  against the frame members  30 ,  32  as the lens  14  slides beneath the lens attachment clip  52 . As before, the resiliency of the frame  20  and/or lens maintains the lens  14  tightly secured within the frame  20 . 
     As illustrated in FIG. 7, the lens  14  can be removed from the frame  20  by applying a force to the upper edge of the lens  14  directed downwardly, i.e., toward the lower frame member  32 , thereby causing the lens  14  to slide from beneath the outer lens attachment clip  52 . After the lens  14  has been removed from the lens attachment clip  52 , its inner edge can be removed easily from beneath the inner lens attachment clip  40 . 
     It should be reemphasized that the installation and removal techniques shown in FIGS. 4-7 are illustrative only and other techniques may therefore be used depending upon the specific lens and frame structure of the eyeglasses. Also, although specific eyewear styles are shown in FIGS. 1-3, it will be understood that other eyewear styles may be devised without departing from the invention. For example, the clips  40 ,  44  may be positioned behind the frame members  30 ,  32  so that the clips  40 ,  42  hold the lens  14  behind the frame members  30 ,  32 . Other variations will be apparent to one of ordinary skill in the art. Furthermore, although the inventive eyeglasses are described primarily as sunglasses, it will be understood that the invention may also be applied to prescription eyewear. 
     From the foregoing, it will therefore be evident that, although specific embodiments of the invention have been described herein for purposes of illustration, various modifications may be made without departing from the spirit and scope of the invention and the claims contained herein.