US1480364A

US1480364A - Reflector

Info

Publication number: US1480364A
Authority: US
Publication date: 1924-01-08
Anticipated expiration: 1941-01-08

Description

Jan. 8 1924.

, L. A. BEAN REFLECTOR Filed April 16. 1923 2 Sheets-Sheet 1 I I l/ U v 127' n m};

IN VEN TOR. law/5 4 5:4

' fi s. Y

A TTORNEY.

Patented Jan. 8, 1924.

UNITED STATES LOUIS A. BEAN, 01? DENVER, COLORADO.

REFLECTOR.

Application filed April 16, 1923.

T all whom it may concern Be it known that I, LOUIS A. BEAN, a citizen of the United States of America, residing at Denver, in the county of Denver and State of Colorado, have invented certain new and useful Improvements in Reflectors, of which the following is a speciflcation.

This invention relates to reflectors and while it is particularly applicable to headlights for automobiles and the like, it will be found valuable in many other forms of lighting installations. 1

Automobile lamp reflectors at present on the market are formed in the general shape of a parabolic conoid, the base of the conoid being the open side of the reflector which presents, in elevation, a circle. This form of reflector naturally projects a beam of light which is circular in cross section. The spread of this beam can be varied within narrow limits by changing the position of the lam in the reflector, but the beam is always in the form of a cone of light. When focused in a narrow beam it illuminates only the road directly ahead of the car and dazzles the approaching motorist. When focused in a wide beam, over 50% of the cone of light is projected upward where it serves no purpose in illuminating the ground or surrounding objects where the illumination is desired and the balance is weak and out of focus.

The basic object of this invention is to overcome the faults and shortcomings of the common parabolic conoid reflector, noted above, by providing a reflector which will project the light in a wide, horizontal. fanshaped flare, which will illuminate to the sides with equal intensity as to the front.

A further object of the present invention is to increase the intensity of the road and ground illumination by projecting the light, that the parabolic conoid reflector projects into the air, upon the ground.

A still further object is to provide a reflector which will intensely illuminate at the sides of the lamp in order that the motorist can at all times view his surroundings and the side roads and turns before he has turned into them.

Other objects and advantages reside in the detail construction of the invention, which result in simplicity, economy and efliciency, and which will become more apparent from the following description.

Serial No. 632,353.

In the following detailed description of the invention reference is had to the accompanying drawings which form a part hereof. Like numerals refer to like parts in all views of the drawing and throughout the description.

In the drawings Figure 1 is a front elevation of the new reflector.

Fig. 2 is a. front elevation of a circular faced lamp showing how the new reflector might be installed therein.

ig. 3 is a profile projection diagram taken on the line 33, Fig. 1.

Fig. 4 is a similar diagram taken on the line 1-4:, Fig. 1.

Fig. 5 is a vertical cross section through the reflector on the line 5-5, Fig. 1.

Fig. 6 is a similar cross section taken on the line 66, Fig. 1.

In the projection diagrams the direct rays are shown by solid lines and the reflected rays by broken lines.

Let the numeral 9 designate the reflector as a whole, which is provided with the usual clamping rim 10 and light source 30.

The rim 10 presents in elevation, as shown in Fig. 1, two equal semi-circular ends 11 and 12, connected by two straight, parallel. tangential sides 13 and 14, thus making the reflector 9 of greater width than height.

The edge of a vertical cross section of the reflector taken through the light source would be practically a perfect parabola, as

shown in Fig. 4. This vertical line through the center of the reflector is the only part thereof which is a perfect parabola. This may be demonstrated by viewing the illuminated reflector from the focus point ahead when a narrow band of brilliancy will be seen extending vertically across the entire reflector.

This parabola is not revolved upon its axis to form a parabolic conoid as in the usual reflector but is extended horizontally each side of the light source to form two triangular parabolic planes and 16. which join the curved ends along imaginary lines 17 which connect the points of tangency 18 of the rim 1() and the midpoint of the re flector 9.

Contour lines, that is, equally spaced parallel lines, drawn upon the parabolic planes 15 and 16 and extending and joining around the ends of the reflector, every point in each line being an equal distance from the plane of the reflector opening, would in every instance form a shape simi lar to that of the rim, that is, two semicircular arcs joined together by two straight parallel lines. The radius of the arcs and the length of the straight lines would diminish in what might be termed parabolic progression as the bottom or mid-point of the reflector was approached.

A cross section taken at 5,5, Fig. 1, and shown in Fig. 5, cuts through partof the parabolic planes l5 and 16, the balance being the curved end portion.

A cross section taken at 66, Fig. l, and shown in Fig. 6, cuts through the curved end portion only, it being beyond the parabolic planes.

Any radial cross section taken through the source of light and cutting the parabolic planes l5 and 16 to either side of, the vertical center line, will not cut a parabola from the reflector, with reference to its axis through the source of light, but will cut what might be termed an extended or flattened parabola. This extensioon or flattening of the parabola progresses practically uniformly from the vertical perfect parabola to the horizontal center lineof the reflector where the curve of the reflector presents the form shown in Fi 3. p

The curve at this point is an empirical curve having its greatest curvature at its extremities and being relatively flat at its mid-portion.

The action of the light rays at the vertical center line or parabolical section is similar to any parabolic reflector and is shown in Fig. 4, they being projected straight ahead, as indicated at 19, and illuminating the middle distance. Practically, however, it is impossible to obtain ,a perfect point of light so that these rays will condense and spread and distribute themselves evenly in the general direction of straight ahead or along the axis of the reflector.

The action of the light rays at the hori zontal section or point of greatest exten sion of the reflector is shown in Fig. 3. It will be noted that the direct-rays of light from the light source spread in a wide fan shaped beam, as indicated at 20. VThe first incident rays to strike the reflector are reflected ahead to blend with, and. assist the previously described rays 19 in illuminating the middle distance as indicated at 21. As the center of the reflector is approached, the reflected rays gradually increase their angle with the axis of the reflector, as shown at 22, intensifying the broad fan of light of the direct rays 20.

The maximum spread of the reflected rays is from the portion of the reflector indicated at 23, where the beams are reflected at a very wide angle, as shown at 2a. From this point on, the rays gradually swing inward again, as indicated at 26, until theoretically the final projection would be along the axis at 25.

The spread of the rays can, of course, be varied by changing the distance of the light source from the reflector. Shortening the distance will increase the spread of the fanshaped beam.

W'hen illuminated and viewed from a point directly ahead, five distinct points of light can be discerned in the reflector; one at each end, caused by the beams 21 striking the eye; one above and one below the light, caused by the divergence of beams 19; and the light source 30 itself. Since this is but a fraction of the light projected, it is not dazzling. or blinding to the eye.

ii hen viewed from one side,,four points of light are usually visible in the reflector; the light source 30; a point beside the light source towards the spectator, caused by the beams 22 or 24:; a point above and a point below the light source causedby incident beams striking the parabolic planes 15 and 16 an angle.

The action of the light beams at the two extremes of the reflector have been illustrated and described, the aotion; at any intermediate section through the light source would vary from the direct beam of section l-tto the extreme wide spreadfof section 3-3 according to its angle from the axis of the entire reflector.

In Fig. 2 is shown an adaption of the new reflector to a circular faced auto lamp housing 31. leave a segment of lens 32 above and 33 below which might be frosted orcoloredias indicated in Fig. 2 of the drawing.

Nhile I have described and illustrated herein a specific form of my improvement, 1 wish it understood that the same may be varied, within the scope of the appended claims, without departing from the spirit of the invention.

Having thus described the invention, what is claimed and desired secured by Letters Patent is M 1. The combination in a reflector, having an oblong opening defined by two parallel straight lines connected by semi-circular ends, of two triangular-shaped surfaces of a base equal to the length of, and coinciding with, said two parallel straight lines and extending back in a parabolic curve to a common apex on the axis ofsaid reflector; and concave surfaces connecting with said semiscircular edges and extending back on a curve to tangential connection with said triangular shaped surfaces and terminating at the axis of said reflector. 2. A transversely elongated reflector comprising upper, lower, and sideportion's all radiating from the vertex of the reflector, the upper and lower portions each compris- The shape of the reflector would ing substantially triangular surfaces presenting an arc of a parabola in a vertical section and a straight line in a horizontal section, the side portions each being curved in a vertical section perpendicular to the mouth of the reflector and curved on an arc of a circle in a vertical section parallel to the mouth of the reflector, said side portions being connected to said upper and lower portions along the radial edges.

3. In a light projecting apparatus, the combination of a reflector having an oblong opening defined by two parallel straight lines connected by semi-circular ends, said reflector comprising a pair of triangular shaped surfaces of a base equal to an coinciding with said two parallel straight lines and extending back on a curve to a common apex on the axis of the reflector, and concave surfaces connecting said semi-circular edges and extending back on a curve to tangential connection with said triangular shaped surfaces and terminating at the axis of said reflector, and a light source arranged in focus with said reflector whereby said triangular shaped surfaces will project substantially parallel rays of light forwardly and said concave surfaces will project diffus ing rays of light to each side of said parallel rays of light.

In testimony whereof I afiix my signature.

LOUIS A. BEAN. Witness:

GEO. J. HUMBERT.