Metal working – Method of mechanical manufacture – Assembling or joining
Reexamination Certificate
2000-12-29
2001-09-04
Hughes, S. Thomas (Department: 3726)
Metal working
Method of mechanical manufacture
Assembling or joining
C029S428000
Reexamination Certificate
active
06282771
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention generally relates to convex, three dimensional mirrors and, more particularly, to a mirror assembly, sometimes referred to as a “cross-over” mirror, which affords a bus driver, for example, a school bus driver, visual access in front of the school bus which is hidden from direct view as well as alongside the bus. Such cross-over mirrors can however also be used at the rear corners of a vehicle such as with trucks, mail vans and the like.
For many decades, cross-over mirrors and mirror assemblies have been deployed on school buses and are in fact required by federal and local regulations. A substantial body of prior art has been published describing various mirrors of the type to which the present invention relates. An exemplary list of such prior art includes U.S. Pat. Nos. 4,822,157; 4,730,914; 4,436,372; 5,084,785; 5,589,984 and Des. 346,357. The above list represents but a fraction of the extensive prior art on the subject of cross-over mirrors and their accessories such as mounting hardware, mirror poles and other implements by which such mirror assemblies are secured to vehicles such as busses, school buses, trucks and the like. The contents of the aforementioned United States patents are incorporated by reference herein.
The convex, three-dimensional surface of the mirror lens described, for example, in the aforementioned U.S. Pat. No. 4,436,372, terminates in a continuous, peripheral edge which is essentially circular. That (and other similar) mirrors have a generally elliptical, i.e. dome, shape.
In more recent years, the prior art has moved to provide convex, three dimensional mirror lens surfaces that have a more stretched, elongate general shape. The aforementioned U.S. Pat. Nos. 4,822,157; 4,730,914; 4,436,372; 5,084,785; 5,589,984 and the Des. 346,357 illustrate the general style of such mirrors.
For the purposes of the present invention it is important to note that, essentially as a rule, the three dimensional, generally elliptical or convex surfaces of the aforementioned elongate cross-over mirror lens were provided with radii of curvature (measured along planar cross-sections) which were measurably non-constant, i.e. tending to increase or decrease from the center point on the mirror lens toward its peripheral, circumferential edge.
As an example, the convex, ellipsoid mirror lens shown in U.S. Pat. No. 4,436,372 has a generally flatter, i.e. less curved, center surface, which surface curves sharper as one proceeds toward the peripheral edge. Stated differently, the “radius of curvature” of the surface decreases from the center where the major and minor axis of the mirror surface intersect toward the peripheral edge of the mirror. A similar relationship is specifically claimed for the elongate, oval mirror that is described in the aforementioned U.S. Pat. No. 5,589,984. In another patent, an opposite relationship is specified—the sharpest curvature is at the center, as the mirror surface flattens out as one proceeds toward the peripheral edge. In the mirror lens of the U.S. Pat. No. 4,730,914, the inventors stress the fact that the mirror surface has a generally constant radius of curvature at a central portion of the mirror representing about one half of the entire surface and different radii of curvature at the other portions of the mirror lens.
In part, the present inventor perceives that the prior art was constrained by the type of technology commonly used in the industry for forming a mirror lens, which technology inherently imparts non-uniform radii of curvature to the mirror lens. Indeed, at least some people adhered to a conventional wisdom that it is desirable to vary the radius of curvature so as to obtain a larger and less distorted image at the mirror center, but a greater field of view, through the provision of a more distorted image, at the peripheral regions on the mirror. The idea is to increase the space that the mirror monitors in and around the school bus or the like.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an elongate, generally oval, convex/ellipsoid mirror lens that improves the ability to discern the movements of children around and about school buses and other types of vehicles.
The foregoing and other objects of the present invention are realized by an oval mirror lens and associated mounting parts which allow the mirror lens to be mounted to a vehicle to provide a field of view in front of and alongside of the vehicle. The mirror lens is oval, substantially convex and has, due to its oval shape, a major axis and a minor axis. These axes intersect one another at right angles at the center point (or apex) of the lens.
The mirror lens has an oval-shaped peripheral edge and the key aspect of the invention resides in the fact that a line traced along the major axis of the lens from one point on the periphery to the juxtaposed, opposite point on the periphery has a first constant radius of curvature. Similarly, a line traced on the surface of the lens along the minor axis from one end point on the periphery to the juxtaposed point on the periphery has a second radius of curvature. The first radius of curvature is larger than the second radius of curvature. The resulting mirror surface produces images of objects which more faithfully maintain the width and height proportions of the object, e.g. a child's image, that is reflected from different portions of the mirror lens.
The present invention also relates to a method for fabricating the mirror lens of the present invention to attain a lens having the constant radii of curvature feature referenced above.
Thus, the present invention revolves around the notion that one obtains a mirror in which the height/width proportions of objects placed around the school bus are subject to less variation, as compared to mirrors of the prior art. By means of the novel mirror of the present invention, a bus driver is less likely to lose sight of a child moving about the school bus, which is of course very important to the safety of our children.
Other features and advantages of the present invention will become apparent from the following description of the invention which refers to the accompanying drawings.
REFERENCES:
patent: 11090964 (1999-04-01), None
Blount Steven
Hughes S. Thomas
Ostrolenk Faber Gerb & Soffen, LLP
Rosco Incorporated
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