US2719967A - Signal lamp - Google Patents

Description

Oct. 4, 1955 H. B. DONLEY 2,719,967

SIGNAL LAMP Filed July 18, 1952 1N VEN TOR.

A TTORNE Y United States Patent Office 2,719,967 Patented Oct. 4, 1955 SIGNAL LAMP Harold B. Douley, Columbus, Ohio, assignor to Columbus Metal Products, Inc., Columbus, Ohio, aV corporation of Ohio t Application July 18, 1952, Serial No. 299,569

6 Claims. (Cl. 340-382) My invention relates to `lamps and more particularly to an improvement in lamps for vehicles.

An object of the present invention is to provide `a` signallamp for vehicles wherein objectionable glare is prevented from striking the drivers eyes by a light interrupting element which is positioned to interrupt certain `directionally uncontrolled rays which would normally be emitted from the lamps.

A further object of the present invention is to provide a signal lamp for vehicles wherein a phantom light effect, produced by external light entering the lamp, is minimized by alight interrupting element.

`Still a further object of the present invention is to provide means for mounting such light interrupting element in a signal lamp. j

The present invention is particularly useful on trucks where it is common practice to mount a turn signal lamp at the apex of each front fender. Each light generally comprises a forwardly directed reflector and a rearwardly directed reflector with the two reflectors having a common light bulb.

Prior to the present invention, certain objectionable characteristics have been present in signal lamps of this type. As certain of the emitted rays from the light bulb pass directly through a lens of the lamp without first contacting a reflector, such rays are not presented tothe lens in a parallel beam. The reflectors used are of the parabolic type which collimate certain of the light rays and present them to a lens in a beam of parallel rays. Hence the lenses used are ofthe type designed to directionally control light received in collimated form. Such lenses are therefore necessarily not of the proper design for directionally controlling certain of the light rays which are radially emitted from the light source and which pass directly through a lens without first contacting a reflector. Certain of these rays, which pass directly from the light source to a lens, are naturally directed to obliquely strike the inner surface of the lens. Heretofore such rays have been permitted to pass through the lens with the objectionable result that some of such rays were directed upwardly by the prismatic effect of the lens causing glare in the drivers eyes. With the present invention, however, the drivers eyes are protected from glare by positioning a light interrupting element or shield in the ray path between the light source and the lens. Such shield is positioned between the lens and the light source, as herein disclosed, so as not to interfere with the normal function of the lamp.

A second objectionable characteristic heretofore present in lamps of this type has also been materially eliminated by the shield just described. In signal lamps of the type having a common light bulb between forwardly `directed and rearwardly directed lenses and reflectors, it

is possible for external light, such as sunlight, to enter the signal through a lens and cause the signal to appear to be` illuminated, particularly when the other lens is viewed by an approaching driver. This artificial illumination, on occasion, indicated false signals, such as incorrect signals of turn, to approaching drivers, and avoidable accidents have resulted. Such artificial :illumination will be herein referred to as the phantom light.`

The shield of the present invention serves to prevent a major portion of the external light rays, which strike a lens, from passing into the turn signal and thereby materially minimizes the phantom light effect in the signal. When the sun is low, as at setting, the rays may become aligned with the aXis of the shield so that the shield becomes less effective, but at such period of the day, the need for the shield is greatly lessened due to the decreased intensity of the suns rays. Hence, as a practical matter, the present device serves to eliminate the phantom light effect from turn signals of the double reflector type. At the same time, the present invention also serves to shield the drivers eyes from objectionable glare.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred form of embodiment of the invention is clearly shown.

` In the drawings:

Fig. l is a side view, partially in section, of a signal light constructed in accordance with the present invention with the section being taken essentially along the line 1 1 of Fig. 2; j

Fig. 2 is a front View, partially in section, of the signal light of Fig. l with the section being taken essentially along the line 2 2 of Fig. l; and 4 Fig. 3 is a broken sectional view showing the means for mounting the shield of the present invention.

Referring to the drawing the signal lamp comprises a casing 10 in which a light bulb 11 is mounted in a socket 12. Two reflectors 13 are shown, and in the presentV embodiment are disposed opposite one another and Within the casing 10. The reflectors are positioned so that the bulb 11 serves as a common light source for casting light upon the surfaces 14 of the reflectors. Each of the reflectors is preferably of parabolic configuration and the two reflectors are positioned so that the foci ofthe parabolas are coincident. The light source 11 is preferably located at the common focal point for the two parabolas. With such preferable configuration, the light reflected from the surface 14 will be collimated sothat` the reflected light reaches a lens 15 in parallel rays.`

I'JIwo of such reflected rays are shown at A and B in As the light source 11 emits rays in all directions, certain of the rays, which are not directed towards a reilector, will pass directly to a lens 15. Referring to the left side of Fig. l, the ray D will be seen passing directly from the source to the lens.` The same would ordinarily be true of certain other rays such as ray C, but since a shield 18 is mounted in the lamp, the normal path of ray C is interrupted at the point where-` ray C strikes the inner surface of the shield 18. The extension of ray C beyond the shield 18 is indicated by short dot segments to show the original path that ray C would follow if it were not deflected by the shield 18.

It should be noted that the rays C and D are not collimated by the reflector, as were the rays A and B, and hence such former rays will be presented to the lens at an oblique angle. Light ray C is provided as a typical illustration of an uncontrolled ray which would produce an objectional effect were the shield 18 not present. The

normal path of the light ray C is seen to be bent sharply wall of the shield at a slot 21a.

3 prismatic effect of the condensing by collimating portion of the lens to substantially align the path of ray D with the path of the controlled rays A and B.

The direct ray C exemplifies the light rays, that are uncontrolled by the ref iector and lens combination which is necessarily designed for directionally controlling the reected light rays, and hence is of an improper design for controlling certain rays, such as ray C, which are emitted directly from the source to the peripheral portion of the lens surface.

As the signal lamp of the present invention is preferably mounted on the apex of a v'ehicles fender, certain of the direct rays, which are directed upwardly at a sharp angle as exemplified by the normalV path of ray C, will cause glare in the eyes of the driver of the vehicle. To eliminate, this glare, a light interrupting element, or shield 18 is interposed in the path of the light rays so that the wall of the shield will blank out the objectionable upwardly directed rays such as ray C of the drawing. With the shield 18 positioned as shown i. e. surrounding the collimating section of the lens, the reflected` raysand certain of the direct rays that pass centrally through the lens, are not deected by the shield 18. Hence the total illumination potential of the light is only slightly lessened by the presence of the shield 18. At the same time, the direct rays which could produce objectionable glare are interrupted by the shield.

Although the shield 18' is shown in the drawing as a tubular element, such tubular shape merely represents a preferred configuration. The illustrated shield can be replaced by' a shield having any other suitable form whereby the objectionable rays are deflected in the manner described herein.

The outer end of the shield 18 preferably extends to the inner surface of the lens 15, and the shield` is pref'- erably made of sufficient length so that the inner end of the shield terminates at the path of ray H as shown in Fig. l. In this manner, all of the objectionable directly emitted rays which are lower than ray H, such as ray C, will be deflected by the shield 18. At the same, time, all` of the rays above ray H, such as rays A and B, will passV to the reector surface, or will at least be prevented from passing directly out through the upper portion of the lens to produce glare in the drivers eyes.

Referring particularly to the reiiector and lens shown on the right side of Fig. l, a ray E of light from an external source is shown passing into the light through the lens a. Such external rays will strike the glass ofthe bulb 11 and the glass of the lens 15, and such rays are diffused by the glass causing such glass to appear to be illuminated by an interior light source. I t should be noted that the externall rays E are free to pass through the apertures 2,5 inthe rear walls of the reectors. Hencethe external rays can enter the lamp throughV one lens and pass through the lamp to the other lens. When the external light is of suflicient intensity, such rays, exemplified by ray E, produce a phantom light effect in the lamp so that such lamp appears to b e illuminated when viewed by an approaching driver. false signal willv be given` and an accident may well be caused. The shield reduces the intensity of the natural lightentering through the lens 15aY of the lamp, and such shield deflects the external light rays which are obliquely presented to the lens 15a, andV thereby prevents such externalv rays from passing directly through the lamp. Such oblique rays are exemplifiedv by rays F and' G in Fig. 1.

The shields 18 are preferably mounted by a plurality" of radially extending mounting brackets 20. Such brackets are preferably in the form of` resilient wires- Each wire is provided with a hook- 251- which engages the As isr shown inthe enlarged view of Fig. 3, each wire 20 is provided with an end portion 22 which extends between an inner surface 25' on the lens and a lens mounting surface 24 on the casing. The end portion 2.2` of the wire 20- is normally In this manner a bowed in the manner shown so that such end portion 22 is normally not aligned with the surfaces 25 and 26. A clamping ring 27 is provided for mounting the lens to the casing. As is best seen in Fig. 3, the clamping ring 27 is of U-shaped cross section, with leg members 28 spaced progressively farther apart towards their ends. Hence when the clamping ring 27 is tightened by a bolt and nut 30, Fig. 2, the ring will force the surface 25 on the lens towards the surface 24 on the casing. When the lens moves towards the casing, the bowed end portion 22 of wire 2t) is clamped into complete alignment and contact with the surface 25 on the lens. The end portion 22 is permitted to conform with the surface due to its inherent resiliency. The tightened position of the clamping ring 27 is shown in Fig. 1,l and the normally bowed end portion 22 is shown clamped into alignment with surfaces 24 and 25. In the tightened position of Fig. l, the wire 20 serves as a spring to constantly urge the shield 18 snugly against the lens. Hence i-t is seen that the shield is mounted in a simple manner, which facilitates its assembly in the lamp. At the same time the shield is held firmly in place by the spring action of wire 20.*

As is best seen in Fig, 3, a gasket 26 is included be-v tween the surfaces 24 and 25 to serve as a weather seal. The reflector 13 is preferably mounted by clamping a peripheral portion 31 between the gasket 26v and the surface 24..

In summary7 itV will be seen that the shield of the presf ent invention provides novel improvements in signal' lamps. The functionalA di'erences resulting from such improved structures are likewise novel, and they exerrt` plify a meritorious advancement in the art.

While the form of embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

I claim:

l. A lamp comprising in combination, a casing having an opening therein; a lens filling said opening; a reflector mounted in the casing; a light source adjacent to the reflector and positioned so that rays, directly emitted from. the source, are emitted towards the entire area of the lens, said light source being positionedy such that Other rays impinge upon the reflector, said lens having a section for substantially' collimating direct rays emitted from thelight source, said lens having a second section adjacent to the collimating section;l and a hollow light interrupter surrounding the collimating section of the lens and ex` tending axially inwardly from the lens and from the boundary of said collimatingI sectionl and toward the light source a distance sufficient to prevent direct rays, emitted from the lightV source, fromv impinging on said second section of the lens.

2. A lamp comprising incombination, a casing having an opening therein; a lens filling` said opening; a. reflectormounted in the casing; a light source adjacent to thelight source and terminating at an imaginary conical sur-A face generated by straight li'nes extending from the light source to the periphery of the lens.

3. A lamp comprising in combination, a casing having an opening therein; a lensfillingI said opening; a re'ector mounted in the casing; a light source adjacent tothe re.-

iiector and positioned so that rays, directly emitted from' w the source, are emitted towards the entire area of' the. lens, said light source being positioned such that other rays impinge upon the reflector, said lens having a section for substantially collimating direct rays emitted from the light source, said lens having a second section surrounding the collimating section; and a tubular light interrupter surrounding the collimating section of the lens and extending axially inwardly from the lens and from the boundary of said collimating section toward the light source a distance sufiicient to prevent direct rays, emitted from the light source, from impinging on said second section of the lens.

4. A lamp comprising in combination, a casing having two openings; a lens filling one of said openings; a parabolically shaped reflector mounted in the casing, the rear of said reflector having an opening therein; a light source adjacent to the reflector and positioned so that rays, directly emitted from the source, are emitted towards the entire area of the lens, said light source being positioned such that other direct rays from the light source impinge upon the reflector and still other rays pass through the other of said openings in the casing, said other opening in the casing being so positioned that light rays from an exterior source could pass therethrough and through the opening in the reflector to the lens, said lens having a section for substantially collimating direct rays emitted from the light source, said lens having a second section adjacent to the collimating section; and a hollow light interrupter surrounding the collimating section of the lens and extending axially inwardly from the lens and from the boundary of said collimating section toward the light source, a distance sufficient to prevent direct rays, emitted from the light source, from impinging on said second section of the lens.

5. A lamp comprising in combination, a casing having two openings; a lens lling one of said openings; a lens filling the other of said openings; a parabolically shaped reliector mounted in the casing in cooperative relation with one of the lenses; a second parabolically shaped reflector mounted in the casing in cooperative relation with the other of the lenses, the rear of each refiector having an opening therein; a light source adjacent to both openings and positioned so that rays, directly emitted from the source, are emitted towards the entire area of each of said lenses, said light source being positioned such that other of the direct rays of the light source impinge on one or the other of said reflectors, said openings in the casing being so positioned that light rays from an exterior source, passing through one of said lenses, illuminates the other lens, said lenses each having a section for substantially collimating direct rays emitted from the light source and a second section adjacent to the collimating section; and two hollow light interrup'ters, one of said interrupters surrounding the collimating section of one of the lenses, the other interrupter surrounding the collimating section of the other of said lenses, each of said interrupters extending axially inwardly, lrespectively, from a lens and from the boundary of the collimating section of such lens to the light source, a distance sufficient to prevent direct rays, emitted from the light source, from impinging on the second mentioned section of the leus from which it inwardly extends.

6. A lamp such as that defined in claim 5 in which the lenses, the openings in the reflectors and the hollow interrupters are axially aligned.

References Cited in the lile of this patent UNITED STATES PATENTS 1,096,452 Perrin May 12, 1914 1,194,758 McCarthy Aug. 15, 1916 1,266,524 Otte May 14, 1918 1,675,731 Schofield July 3, 1928 2,058,546 Haines Oct. 27, 1936 2,243,448 Wells May 27, 1941 2,327,144 Stam Aug. 17, 1943

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