US2074246A

US2074246A - Traffic signal

Info

Publication number: US2074246A
Application number: US106247A
Authority: US
Inventors: Jr Charles Adler
Original assignee: Individual
Current assignee: Individual
Priority date: 1936-10-17
Filing date: 1936-10-17
Publication date: 1937-03-16
Anticipated expiration: 1954-03-16

Description

March 16, 1937. c ADLER' JR 2,074,246

TRAFFIC S IGNAL Filed 001:. 17, 1936 Patented Mar; 16,- 1937' UNITED STATES PATENT OFFICE TRAFFIC SIGNAL Charles Adler, Jr., Baltimore, Md. Application October 17, 1936, Serial No. 106,247

3 Claims. .(01. 117-329) means must be provided to overcome this hazard.

to be observed by an ofiicer and the signal restored 15 to normal.

, In accordance with the invention, a diffusing lens and a reflector in combination witha lamp having main and secondary filaments is employed, the filaments being longitudinally spaced and the filament adjacent the lens having a considerably longer life and lower Wattage than the main filament. The main filament is disposed in focus with the reflector so that substantially parallel reflected rays are utilized to present a 25 normal full illumination of the signal area. The secondary filament is arranged out of focus with the reflector and relatively, closer to the cover glass, whereby, when the main filament burns out, the direct rays form the low wattage longer 30 life secondary filament in combination with the diffusing lens, illuminates the signal in the form of a definite illuminated spot visibly of less area than the signal area. Thus, the signal remains operative, but an officer, and others may ob- 35 serve that the signal is not functioning normally and make report to the proper authority.

Referring to the drawing: Figure 1 is a top view partly in section of one form of the invention; 40 Figure 2 is a similar view of a modification in which a diffusing means is formed on the bulb; Figure 3 is an elevation of the cover glass or lens when the main filament burns out showing the definite illuminated spot provided by the sec- 45 ondary filament and diffusing lens, and

Figure 4 is a similar view with a lens of modified structure. I

Referring to Figure 1, I have shown a diffusing lens or cover glass constituting the signal area 50 at Ill, such lens consisting of a multiplicity of prisms on its interior surface which may take various forms. The reflector is indicated at H and is preferably of the parabolic type as shown. The cover glass or lens and the reflector form 5 a signal housing within which is positioned the illuminating means comprising the incandescent lamp l2 of the gas filled or evacuated type. This lamp includes a bulb I4 of clear glass, one end of which is sealed into a screw threaded base I5, and has the usual stem l6, and pillar H. The 5 main filament carried by the pillar is indicated at I8, and for purposes of illustration will have,- for example, a life of .about 1500 hours and a wattage, for example, of about 25 watts to 50 watts. The secondary filament I9 is disposed in 10 longitudinal alignment on the pillar with but in spaced relation to the mainv filament as shown, and will have for purposes of illustration a life of about 3,000 hours and a wattage of substantially 7% watts to 10 watts.

The spacing of the filaments is important for several reasons. Referring to Figure 1, the main filament is so disposed as to be in focus with the reflector whereby the parallel reflected rays are utilized to present a normal full illumination of the signal area or diffusing lens. Further, the secondary filament .is so disposed as to be out of focus with the reflector and being relatively closer to the diffusing lens, when the main filament burns out, the direct rays from the low wattage longer life filament in cooperation with the diffusing lens, illuminates the signal in the form of a definite illuminated spot visibly of less area than the signal area as shown in Figures 3 and 4.

The distance of spacing of the filaments on the pillar in longitudinally spaced relation, moreover, is such that when one filament, for example the main filament burns out, there is no danger of arcing such as would destroy the remaining filament. a

The filaments are permanently and completely electrically connected in parallel, preferably as shown at 20 through the main lead wires 2| and 22 within the lamp and the base has the usual electrical connection with a lamp socket, e. g. the lead wire 2| terminates at the insulated bottom of the base and the lead wire. 22 terminates at the threaded ferrule surrounding the base. The filaments are preferably circular as shown, but similar elongated filaments of other types may be found satisfactory.

Referring to Figure 2, the lamp has a frosted 'or transluscent tip or end 25 of an area to diffuse the direct rays from the secondary filament in order to produce an illuminated spot as shown in Figures 3 and 4. This lamp may be used with a diffusing lens but is particularly useful where the cover glass has little light diffusing properties or is entirely devoid of the same.

The lens illustrated in Figure 4 is in accordance with my Design Patent 92,055, April 24, 1934, and the prisms are indicated at 23 and corrugated areas at 24.

As will be observed, when the signal is in operation, both filaments are energized and incandescent, and the signal area is fully illuminated by the main filament to give the required signal. When this main filament burns out, the longer life low wattage filament remains illuminated and produces in cooperation with the difiusing means, namely the lens, the frosted area, or both, a definite illuminated spot as shown in Figures 3 and 4. This spot being smaller in area than the total normal illuminated area of the signalis quite definite and visible to an officer, maintenance force or the public so that the failure of the main filament will be observed and the signal restored to normal. The invention is simple, thoroughly reliable, as will be appreciated, and will serve to curtail substantially accidents due to the burning out of the electric lights in the signal system.

I claim:

1. A signal comprising a reflector and a light diffusing cover glass, illuminating means positioned between the cover glass andsaid reflector, said illuminating means comprising electrical light sources arranged in longitudinal relation and connected in parallel, one of said light sources disposed in the focal plane of the reflector for causing substantially parallel reflected rays to illuminate the signal area and another having a longer life disposed out of the focal plane of the reflector.

2. A signal comprising a reflector and a diffusing cover glass, illuminating means positioned 1 between the cover glass and said reflector, said illuminating means comprising electrical light sources arranged in longitudinal relation and connected in parallel, one of said light sources having a high wattage and disposed in the focal plane of the reflector and another thereof having a lower wattage but a longer life and disposed out of the focal plane of the reflector.

3. A' signal comprising a reflector and a light diffusing cover glass, illuminating means positioned between the cover glass and said reflector, said illuminating means comprising electrical light sources arranged in longitudinal relation and connected in parallel, one of said light sources disposed in the focal plane of the reflector for causing substantially parallel reflected rays to illuminate the signal area and another having a longer life disposed out of the focal plane of the reflector, said diflusing cover glass and reflector in cooperation with said light source having the longer life producing on said diffusing lens when the other light source fails, a definite indication of such failure.

CHARLES ADLER, JR.