US1363073A - Headlight - Google Patents

Description

W. G. WOOD.

HEADLIGHT.

APPLICATION ,FILED AUG-15, 1918.

Patented Dec. 21, 1920.

Inzenior Willim G. "60d a. troop, or

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X or we t l7? a in l tart 1L,3E3,@'?f3 specification oi ll-otters Patent.

Application filed nue ust serial 1%.

To all whom it may concern Be it known that l, WILUAM Ween, a citizen of the United States, residing at Berkeley, in the county of Alameda and State of -California, have invented new and useful improvements in Headlights, of which the following is a specification.

This invention relates to headlights such as are employed on automobiles, locomotives and the like, and particularly to improvernenm on the structure shown in my co-pending application entitled, liteadlight, filed au ust 5, 1918, Serial No. 2%,303.

In the present invention, 1 provide a lamp which, following generally the principles of the lamps disclosed in the above mentioned application, employs a reduced light ereitting aperture through which a cone-shaped beam of sharp outline is projected. When the observer is not directly in the path of the beam, the only point of illumination on such a lamp is the small lens which fits in the reduced light emitting aperture. This lens can be seen from various points of angularity forwardly of the lamp. lo the present case, I extend a hood out over the light emitting aperture, said hood serving; to conceal the lens at all times except when the observer is directly in the path of the beam. lhus, for all practical purposes, 1 ani enabled by the employment of this hood to provide a lamp capable of projecting a suitable beam of great intensity and wherein the source of the light is effectively concealed. In the case of an automobile headlight, the uppermost rays of the cone-shaped beam are kept below a horizontal line, and hence nothing is illuminated but the ground some'distance ahead.

One form which my invention may assume is exemplified. in the following'description and illustrated in the accompanying draw ing, in which Figure 1 is a central, vertical, longitudinal section through the headlight, or 'what might be termed a side elevation in section.

Fig". 2 is a front view of the same.

Referring to the drawings in detail, A indicates in general the headlight casing. By referring to the drawings it will be. seen that it is oblong and circular in shape, and that it consists of two sections such as shown at 2 and 3, said sections being secured toportion of the casing section ll at 5 is a I transparent window or aperture, which is mounted a condensing lens '8 of the piano- .convex type, said lens being secured in a screw cap 7, or any other suitable means to a permit it to be readily removed lfor or otherfpurposes.

Mounted-in the rear portion of the casing; is a parabolic reflector 8 and secured in soclret 9 within the reflector is an electric bulb l0 of the usual construction. This bulb is preferably adjustable longitudinally to permit a perfect focusing of with relation. to the parabolic reflector.

Secured in any suitable manner of the parabolic reflector is condsnsi lens ll. and interposed between said. the opening 5 is a plurality of annular plates 12. These are provided central openings as shown at 13 throu h which the light rays to projected pass. The openings 13 in the respective de" crease in size as they a preach the aperture 5, this being due to the fact the rays condensed by the lens ll assume the form of a cone-shaped beam which has its focal point approximately in aperture 5. Secured to the cap 7, or, if desired, to the casing 2, is a shield llhis shield is coneshaped to conform with the light beam pros jected through the aperture 5, or the lens ll, its lower side is preferably cutaway as shown at 15.

By referring to Fig. 1 it can readily be seen that if the bulb 10 is properly focussed a beam of substantially parallel rays will be projected against the lens 11 by the para 'bolic reflector. The rays received by the lens from the reflector when passing through the sarne are condensed or converged, and are thus brought to a focal point in the aperture 5. They will at the saine time spread or diverge after passing through said aperture,

and it can, therefore, be seen that a cone shaped beam is projected, due to the fact that a condensing lens of the plane-convex type is inter osed between the parabolic redoctor and t e transparent aperture. The beam projected through the aperture has the appearance of a cone-shaped beam with the apex of the cone at the aperture, and the Mill aperture through which it is projected is,

practically speaking, invisible, due to the fact that the rays are brought to a focal point in the aperture, and also due to the ills fact that a surrounding shield 14 is employed. It is, therefore, impossible for an observer stationed ahead of the headlight, particularly on either side thereof, to see any visible source of light, except when entering the beam of light projected. This is of great importance when driving an automobile, as the objectionable glare generally produced by headlights is, in this instance, entirely eliminated, due to the fact that no rays are projected above the horizontal line shown at 16. All stray rays caused by imperfections in the reflector 8 or the condensing lens 11 are retained within the headlight, due to the fact that they will either strike the interior surface or the baffle rings 12;

While a specific form of lens is interposed between the transparent aperture and the parabolic reflector 8, I wish it understood that any other form of lens or means capable of the same function, may be employed.

Similarly, that the materials and finish of the several parts forming the headlight may be such as the experience and judgment of the manufacturer may dictate.

Important factors to the successful projection of a concealed source of light are (a) employment of a reduced light emitting aperture; (6) projection of a sharply defined cone-shaped beam therethrough; and (0) a hood of about the same divergence as the rays of the beam so that the light rays are not obstructed, such hood being extended far enough ahead to conceal the lens in the light emitting aperture when the observer is out of the direct path of the beam of light. If the hood obstructs the light rays, its interior will thereby be illuminated and also a fringe will be formed around its ed e which will be plainly visible to one stan in outside of the path of the beam.

illaving thus described my invention, what I claim and desire to secure by Letters Patent is:

1. In a lamp, a casing having a reduced light emitting aperture,-a source of light in the casing, means for projecting a coneshaped beam through the reduced aperture, and a hood on the casing surrounding the light emitting aperture but out of interference with the projected beam, said hood being extended far enough ahead to conceal the light emitting aperture from view when observed from any point not in the direct path of the projected beam.

2. A headlight comprising a casing having a small transparent aperture formed therein, a source of light in the casing, means cooperating with said light, adapted to project a cone-shaped beam through the transparent aperture, said beam having a focal point in the aperture at which the light rays of the beam cross, a lens in the aperture, a baflie ring within the casin positioned adjacent the focal point of the beam, said ring having a central opening formed therein which is sli htly less in diameter than the cone-shaped beam projected therethrough, and a shield exterior of the casing partly surrounding the,transparent apertures through which the cone-shaped beam is projecte 3. A headlight comprising a casing having a transparent aperture formed therein, a source of light in the casing, a parabolic reflector surrounding said light, means interposed between the reflector and the transparent aperture adapted to concentrate and converge the reflected rays from the para:

bolic reflector to a common focal point before they are projected through the transparent aperture, and means for rendering the transparent aperture invisible to an observer stationed in front of the headlight,

except when standing directly in the beam projected.

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses. g

Y WILLIAM G. WOOD.

Witnesses:

JOHN H. HERRING, W. W. HEALEY,

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