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603,799 · Sullivan · "Illuminating-Lens for Sidewalks" · Page 2 Home  > Prism Glass  > Patent Index  > Page 2

603,799: 2 of 5

said triangle and the rear surface the hypotenuse thereof. As seen from the front, or in face view, the leg is of rectangular form, with parallel vertical side edges or faces and a horizontal lower edge. The base of said leg is of less width from front to rear thereof than the distance between its side edges, and the said front vertical surface b intersects the bottom surface of the body portion of the leg at some distance from the adjacent edge of the said body portion, while the sides and rear surfaces of the leg extend to and practically coincide with the side and rear margins of the said body portion. The front surface b of the leg therefore is a plane surface extending the full width and length of said leg, as shown clearly in Fig. 2 of the drawings, and will desirably be formed nearly in a vertical plane or at right angles to the plane of the upper surface of the body portion, but preferably at a slight inclination from a vertical line, as shown. The rear portion of the leg is composed of three plane triangular oblique surfaces or facets b' b² b³, each lying in a different plane with respect to the plane of the front surface b of the leg. The middle oblique surface b' extends the full width of the leg at the bottom thereof and the lines forming its outer edges converge upwardly and intersect each other at the base of the leg at a point midway between the side edges thereof. The lateral oblique surfaces b² and b³ are bounded at their rear edges by said converging lines forming the outer edges of the middle oblique surface and at their outer edges intersect the outer perpendicular side faces b4 of the leg, said side faces being located in vertical planes at right angles to the plane of the front face b. The termination of the depending leg short of the extreme front surface of the body portion forms adjacent to said front surface b, at the under side of the body portion, a downwardly-facing surface b', which lies parallel with the upper surface of said body portion.     In a lens constructed as described rays of light passing through the body portion outside of the front vertical face of the leg will pass vertically therethrough and into the inclosed space within. By the provision of the three plane surfaces or facets disposed in different planes with respect to the vertically-arranged front surfaces of the leg the rays of light passing perpendicularly through the lens and striking the said surface will be reflected forward, as shown in Fig. 5, at three different angles, those reflected by the middle facet b' passing straight forward at a slightly-downward inclination, while those reflected from the side facets will converge and cross each other (and also the rays reflected from the middle surface) at a point forward of the leg, the distance of such point from the leg depending upon the angular relation of said side surfaces to the middle surface. By reason of the fact that the central facet extends across the full width of the leg at the extremity of the same a large reflecting-surface

will be formed near the extremity of the leg, by which a large portion of the light-rays which pass through the central part of the lens will be thrown forward through the flat front face of the leg into the apartment to be lighted. At the same time the lateral oblique facets will reflect and disperse laterally the rays entering nearer the side margins of the lens. By this arrangement of the oblique reflecting surfaces or facets of the lens, therefore, the dispersive powers thereof will be very large and the rays of light transmitted therethrough will be distributed strongly and uniformly in the space opposite the lens and throughout the space to be illuminated forward of the depending leg, which is entirely outside of the direct range of the rays of light from the lens. The termination of the leg in the rear of the front vertical surface b of the body portion B' affords also means for the direct transmission of vertical rays of light, so that the inclosed space receives light to illuminate the space immediately adjacent to the lens, as well as to illuminate the space outside of the place which the direct rays may enter.     The lenses made as hereinbefore described—namely, with hexagonal body portions and depending legs having flat front faces b—will be arranged in the supporting frame or plate, as shown in Fig. 9, in parallel rows, the lenses of each row being arranged with their side faces b4 side by side and parallel with each other and the said flat faces b in alinement with each other. The lenses thus arranged in rows will be so disposed that the lenses of each row will be opposite the spaces between the lenses of adjacent rows, this arrangement bringing the several adjacent side edges of the hexagonal body portions parallel with each other, as seen in Fig. 6, and thereby enabling a maximum area of light-transmitting surface to be obtained, combined with a minimum area of metal between the lenses. The most important advantage of this arrangement, however, is obtained from the location of the vertical flat front surface b of each lens opposite or behind the space between the legs of the lenses in front of it, this construction insuring that light thrown forward from the central part of each lens will pass through the space between the two adjacent lenses in front of it, thereby producing not only a maximum of lighting effect, but uniformity of distribution of the light thrown into the apartment by the lenses.     Tile lenses will be located at such distances apart with relation to the size and the angles of the reflecting-surfaces that the light reflected and dispersed thereby will be distributed uniformly—that is to say, it the pendent leg be made shorter than herein shown the lenses will be mounted closer together the plate A, or vice versa.     I claim as my invention—     1. An illuminating-lens comprising a hexagonal body portion and a leg projecting from