The term"eyewear"is interpreted broadly to include anything which is worn about the head of an individual with portions thereof extending in front of the wearer's eyes. Examples of eyewear include spectacles, sunglasses and goggles, for example.

Lenses for eyewear may serve a variety of purposes, e. g., for sight correction (Rx) and/or achieving special optical characteristics such as photochromic and polarized lenses.

Sunglass lenses are used to protect the eyes from bright light and may include UV filters as well as other filters which act on certain frequencies of the electromagnetic spectrum to produce what is regarded as a"specialty"lens since it is intended to achieve a certain visual affect for a person looking through the lenses.

The material from which eyewear lenses are made may also vary. The two most common eyewear lens materials are glass and plastic (polycarbonate). Glass is usually considered to have superior optics and durability over plastic lenses, while plastic lenses are generally lighter and cheaper than glass lenses.

Given the variety of lenses available, the ability to change between different types of lenses on a single eyewear frame is generally regarded as a desirable characteristic of an eyewear frame. The well-known"clip-on"type of sunglass lenses to be fit over prescription lenses is an example illustrating the desire to be able to alternate between different lens types on an eyewear. However, the clip-on has drawbacks such as the bulky appearance and weight it adds to the eyewear. Other non-clip-on examples of eyewear frames which incorporate means to change between different types of lenses may be seen in the following patents: U. S. Patent No. 4,523,819 issued to Optyl Eyewear on Jun. 18,1985 U. S. Patent No. 4,759,622 issued to Optyl Eyewear on Jul. 26,1988 U. S. Patent No. 4,822,158 issued to Optyl on Apr. 18,1989 U. S. Patent No. Des. 263,479 issued to Bausch & Lomb on Mar. 23,1982 U. S. Patent No. 5,467,148 issued to Bausch & Lomb on Nov. 14,1995 The sampling of above patents illustrate the variety of techniques used in the design of an eyewear frame to allow the interchangeability of lenses within the frame.

While the above patents include a mechanism with the capability to interchange the lenses on the frame, it will also be noticed that the mechanism is a very prominent feature and thus dictates the overall aesthetic design of the eyewear. Thus, the ability to be able to use the same mechanism within different eyewear styles is strictly limited in these prior designs.

Another important consideration is the manner by which the lenses are secured to the frame. The lenses must be secured in such manner that they do not accidentally release from the frame, but should also be easily releasable when switching to a different set of lenses.. If the securing means is too strong, it raises the risk of damage to the lenses, especially the edges of glass lenses which are prone to chipping. If the securing means is too loose, it raises the risk of accidental release of the lenses from the frame during use.

The mechanism thus needs to achieve a proper balance between these two opposing design criteria.

Summary of the Invention The present invention successfully addresses the above drawbacks and concerns with prior eyewear frame designs having interchangeable lenses by providing an eyewear frame having an interchangeable lens mechanism which blends into the bridge area of the frame such that it essentially unnoticeable when the eyewear is worn. The interchangeable lens mechanism of the present invention may be regarded as a"benign"design component of the overall aesthetic appearance of the eyewear, and is thus easily incorporated into a variety of eyewear frame designs without itself becoming a prominent feature of the eyewear design. Furthermore, the interchangeable lens mechanism of the present invention and the frame cooperatively interact to safely secure the lens pair to the frame while also permitting very easy and quick alternate release and securement of different lens pairs from and to the frame, respectively.

More particularly, the invention provides a"double"frame design which provides an eyewear frame having a rear frame portion and a similarly configured front frame portion between which a pair of lenses are sandwiched and secured in the assembled condition of the eyewear frame. The rear frame portion is formed as a unitary piece having right and left eye openings wherein the lenses are held in the assembled condition.

The front frame portion also includes right and left eye openings but is split at the bridge into right and left portions. The rear and front frame portion are hinged together at the outer, lateral end portions thereof whereby the right and left front frame portions may be opened and pivoted away from the rear frame portion to expose the lenses for access, removal and replacement.

The interchangeable lens mechanism is provided at the bridge area of the frame and comprises a rotating member which alternately engages and disengages the nasal area of each of the right and left front frame portions to alternately secure and expose the lenses within the frame, respectively. In the engaged position, the interchangeable lens mechanism blends into the front frame portion so as to be essentially unnoticeable as a separate working component.

Brief Description of the Drawings Figure 1 is a front, elevational view of a fully assembled eyewear according to the present invention; Figure 2 is a front, perspective view thereof ; Figure 3 is a rear, perspective view thereof with the temples partly broken away; Figure 4 is a front, perspective view thereof showing the right front frame portion pivoted away from the rear frame portion and a right lens in spaced relation thereto; Figure 5 is a front, elevational view of the eyewear showing the interchangeable lens mechanism rotated approximately 90° from the secured position; Figure 6 is a cross-section view as taken generally along the line 6-6 in Fig. 5; Figure 7 is a cross-section view as taken generally along the line 7-7 in Fig. 1; and Figure 8 is a fragmentary, perspective view, partly in cross-section as taken generally along the line 8-8 in Fig. 5.

Detailed Description Referring now to the drawing, there is seen in the figures an eyewear designated generally by the reference numeral 10, having a front 12 and right and left temple members 14,16, respectively. The front 12 includes right and left eye openings wherein a pair of right and left lenses 18,20 may be secured in the manner to be described. A nose pad 11 may be provided at the rear facing surface of the front frame 12. While the invention is described with regard to the particular embodiment shown in the drawing figures, it is understood that the invention is not so limited, and may indeed be incorporated into a variety of eyewear designs as will be apparent to one skilled in the art.

As discussed above, the present invention provides an eyewear frame having an interchangeable lens mechanism to enable a user to remove and replace lenses within the frame as desired. The different lens sets may be of any type, including, but not limited to those having different optical properties, and/or those having different colors.

As seen best in Figs. 3-8, eyewear front 12 is of"double"construction, and includes a rear frame portion 22 having right and left eye openings 22R and 22L, a bridge area 22B therebetween, and opposite lateral end portions 21,23, respectively. Eyewear front 12 further includes a front frame portion 24, configured generally similar to rear frame portion 22, having right and left eye openings 24R and 24L and opposite lateral end portions 25,27, respectively. Right and left eye openings 24R, 24L are movable independent of each other and of rear frame portion 22. As seen best in Figs. 3,4 and 8, a double hinge is provided between each of the temples 16,18 and front 12 whereby front frame portion 24 may be pivoted away from rear frame portion 22 on the one hand, and temples 16,18 may be pivoted with respect to the assembled front frame 12 so that the temples of eyewear 10 may be alternately opened and folded with respect to the front frame in the ordinary manner of eyewear frame construction.

More particularly, as seen best in Fig. 8, a hinge component 30 is provide which includes independent pivot action between paired tabs 30a, 30a' and 30b, 30b'. The upper tab pair 30a, 30a' are fixed to temple 16 and rear frame end portion 21, respectively, while the lower tab pair 30b, 30b' are fixed to temple 16 and front frame lateral end portion 25, respectively. Thus, both the rear and front frame portions 22,24 are independently pivotally connected to temple 16. The same is true at the opposite temple 14 (Fig. 3).

As seen in Fig. 4, since front frame eye openings 24R, 24L are separate components, they may be individually pivoted with respect to rear frame component 22.

As a front frame eye opening 24R, 24L is pivoted in a direction away from rear frame portion 22, the associated temple 14,16 is pivoted therewith (toward the folded position) due to the abutting surfaces of the temple and front frame eye openings which create the seam lines 14S and 16S. When pivoting the front frame eye openings in the reverse direction (toward the rear frame portion 22), the temples may need to be separately moved to the open position.

Referring to Figs. 4, and 6-8, it is seen that rear frame portion eye openings 22R, 22L each include a recess 22R', 22L' about the inner periphery thereof wherein the periphery 18', 20' of the associated lens is laid when inserting the lenses into the frame, respectively. Likewise, front frame eye openings 24R, 24L each include a recess 24R', 24L' about the inner periphery of the side thereof facing rear frame portion 22. The dimensions of the recesses and the associated lens are such that the lens is"sandwiched" between the rear and front frame portions in the assembled condition of the frame, as seen in Figs. 6 and 7, with the lens periphery residing between the area between the recesses.

An interchangeable lens mechanism 36, which allows alternate removal and replacement of pairs of lenses to the frame, is rotatably mounted to the bridge 22B of rear frame portion 22. Figs. 1-3 show the mechanism 36 is its"home"position which engages mechanism 36 to front frame portions 24R, 24L and secures the rear and front frame portions 22,24 together with a pair of lenses 18,20 sandwiched therebetween as discussed above. As seen in Figs. 4 and 5, mechanism 36 may be manually rotated either in the clockwise or counter-clockwise direction to a"release"position which is approximately 90° offset ofthe"home"position. In the release position, mechanism 36 is disengaged from front frame portions 24R, 24L which allows the user to pivot the portions 24R, 24L away from rear frame portion 22 to thus expose the lenses 18,20 for removal from the frame, and replacement with a different set of lenses (not shown). The engagement/disengagement means between the mechanism 36 and front frame portions 24R, 24L are provided in the form of a pair of nubs ni, n2 and n3, n4 located on each of the recessed nasal surfaces 24RN, 24LN of front frame portions 24R, 24L, respectively, and a single nub n5, n6 located on opposite sides of the rear surface 36'of mechanism 36. Thus, upon rotating mechanism 36 from the release position to the home position, nubs n5, n6 cam over nubs ni, n2 and n3, n4 until nubs nus, nu become located between their associated pair of nubs ni, n2 and n3, n4., respectively. The height and configuration of the nubs should be made so as to allow easy rotation of mechanism 36 while also inhibiting the accidental rotation and disengagement thereof.

Mechanism 36 may be mounted to rear frame portion 22 by a shoulder screw 40 passed through rear frame portion 22 and into mechanism 36, and including a thrust washer 42 located in space S, between mechanism 36 and rear frame portion 22.

The rear surfaces of front frame portions 24R, 24L each include a locating boss Bl, B2, respectively, adjacent the nasal areas thereof, which bosses Bl, B2 align with and engage recesses Ri, R2 provided on the front facing surface of rear frame portion 22, also located adjacent the nasal area thereof. Locating bosses and recesses BIRI, B2R2 are provided to establish and maintain proper position of the rear and front frame portions 22,24 in the assembled condition.