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Publication numberUS3780285 A
Publication typeGrant
Publication dateDec 18, 1973
Filing dateJul 24, 1972
Priority dateJul 24, 1972
Also published asCA993422A1, DE2337379A1
Publication numberUS 3780285 A, US 3780285A, US-A-3780285, US3780285 A, US3780285A
InventorsAppeldorn R, Ljungkull G
Original AssigneeMinnesota Mining & Mfg
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Traffic light conversion kit
US 3780285 A
A kit which may be added to a conventional eight inch traffic signal to convert the traffic signal to a larger, i.e., 12 inch signal. The kit comprises a light diffusing roundel of colored glass positioned within the focus of a front positive Fresnel-type lens.
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Description  (OCR text may contain errors)

United States Patent [191.

Appeldorn et al.

1 1 TRAFFIC LIGHT CONVERSION KIT [75] inventors: Rober H. Appeldorn, White Bear Lake; Giir'i'iiaF'R, Ljuri'g'klilh'white Bear Township, Ramsey County, b f

[73] Assignee: Minnesota Mining and Manufacturing company, St. Paul, Minn.

221 Filed: July 24,1972

21 App1.N0.:274,343

240/4645 [51] int. Cl. F2lr 13/04 [58] Field of Search 240/413, 41.5, 41.55,

[56] References Cited UNITED STATES PATENTS 3,457,400 7/1969 Appeldorn 240/41.3 X

[451 Dec. 18,1973

2,484,136 10/1949 Wells 340/383 3,696,715 10/1972 Jedlicka 95/1 R 3,049,614 8/1962 Eikenberry 240/413 3,597,606 8/1971 Abendroth 240/413 Primary ExaminerRichard M. Sheen Attorney-Kinney, Alexander Sell, Steldt & Delahunt [57] ABSTRACT A kit which may be added to a conventional eight inch traffic signal to convert the traffic signal to a larger, i.e., 12 inch signal. The kit comprises a light diffusing roundel of colored glass positioned within the focus of a front positive Fresnel-type lens.

6 Claims, 2 Drawing Figures TRAFFIC LIGHT CONVERSION KIT BACKGROUND OF THE INVENTION This invention relates to a unique optical system which may be positioned as a substitute for the existing lens on a traffic signal to produce an enlarged signal light with the existing light source. One aspect of the invention is the diffusion of the collimated light from a lamp and parabolic reflector by a roundel having a ground surface, which light is collected and collimated by a Fresnel lens to produce the signal.

It is necessary to increase the visibility of signal lights to make them more apparent to the motorist because of the high speeds which are involved in travel on the roads. It would be a heavy burden on the taxpaper should a municipal traffic department replace all of the existing conventional signal lights with larger signal lights to provide the increased protection which has become necessary. The optics for providing new signal lights having a larger size signal is very possible but a need to convert an existing light to the larger signal to increase the size of the ball of light be it red, amber, or green, with the existing available light has resulted in the novel solution defined by the present invention.

SUMMARY OF THE INVENTION The present invention relates to a kit for converting an existing traffic signal having a view surface approximately 8 inches in diameter to an enlarged signal of approximately ll inches by replacing the existing front lens in the existing signal with a kit. The signal conversion kit comprises a colored glass light diffusing roun del supported in a housing and spaced from a short focual length positive Fresnel-type lens. The spacing is less than the focal length of the lens and the roundel is substantially within the focus of the Fresnel lens. The roundel has a size corresponding to the replaced front lens of the traffic signal to be fully illuminated from the lamp and collimated parabolic reflector. Diffuse light from the roundel is collected by the Fresnel lens and produces a large visible bright signal. A sun shield prevents the light from being washed out by the ambient light. The optic axis of the Fresnel is positioned at an angle of from the axis of the parabolic reflector to direct the light toward the traffic.

DESCRIPTION OF THE DRAWING The present invention will be more fully understood after reading the following detailed description which refers to the accompanying drawing wherein:

FIG. I is a side view of a traffic signal lamp having the kit of the present invention mounted thereon; and

FIG. 2 is a vertical sectional view, part of which is not taken along the same section lines, to show the interior elements of the conversion kit.

DETAILED DESCRIPTION The present invention relates to a kit for economically converting the presently conventional 8 inch traffic signal to a larger signal structure. The kit effectively converts'the 8 inch traffic signal light to a light of approximately l2 inches in diameter.

The conventional traffic signal for one signal light comprises a rectangular housing 5, having dimensions approximately inches by 10 inches by 4% inches. The front of thehousing is formed by a hinged door 6. The door '6 is formed with an enlarged circular opening 7 in which is conventionally mounted a light directing lens similar to that of a flood lamp. This lens is usually made of colored glass to project the red, amber, or green light. The traffic signal also comprises a conventional traffic signal lamp 8 mounted in a suitable socket 9 in the center of a parabolic specular reflector 10. The reflector l0 collimates light and would fill the opening 7 with light from the lamp 8.

The kit of the present invention comprises a frame I2 formed of generally trapezoidal shaped sides such that the frame converges from an enlarged planar forward end toward a smaller rearward planar end inclined to the forward end. The smaller end is adapted to be secured to the door 6 of the traffic light by suitable fas teners 13. The fasteners are screws received in threaded openings in the door 6.

A light diffuser in the form of a rough-surfaced roundel 14 formed of conventional molded colored glass is secured in the door 6 in place of the lens of the conventional traffic signal. The roundel is thus held by the fastening means provided for the conventional lens. The roundel has a diameter of 8 inches and an outer radius of 8% inches. The inner surface is ground to diffuse the light. One of the fastening members is illustrated in FIG. 2, and four such fasteners for the roundel and frame are positioned about the opening in the door 6.

Spaced from the roundel 14 and positioned with its axis at an angle of 5 to the axis of the roundel l4 and the reflector 10 is a Fresnel-type positive lens 20. This Fresnel-type lens has an 8 to 10 inch focal length preferably approximately 9 inches which disposes the focal point of the lens behind the light source provided by the lamp 8 and reflector I0. The focus of the lens 20 however is shown by the broken lines 22 and covers a substantial portion of the roundel 14, which roundel is spaced from the lens by about 4 inches. Thus substantially all the diffuse light from the roundel I4 is gathered by the Fresnel lens 20 and is directed toward the roadway. If part of the roundel is outside the focus of the lens 20 the inensity of the signal light would decrease, which should be avoided.

A sun shield 24 is disposed about a circular flange 25 formed on the front of the frame 112 to shield the lens 20 from the ambient light.

Having thus described the present invention with reference to a preferred embodiment, it is to be understood that minor changes may be rnade in the structure without departing from the spirit or scope of this invention.

What is claimed is:

l. A kit for enlarging the size of the surface to be viewed on a traffic signal comprising:

a frame having an enlarged open end disposed in a first plane and a reduced open end disposed in a second plane, said reduced open end being adapted to fit over the open forward end of a traffic signal a Fresnel-type condensing lens defining an axial beam converging at a focal point 8 to 10 inches from said lens and disposed in and supported in the enlarged open end of said frame for providing an enlarged surface to be viewed, and

a light-diffusing diffuser disposed at the reduced open end of said frame and extending across the beam and being substantially within the confines of the beam, said diffuser having a convex surface facing towards said Fresnel-type condensing lens, said reduced open end of said frame being spaced a predetermined distance from the enlarged open end of said frame such that at least a portion of said diffuser is disposed closer to said Fresnel-type condensing lens than to the focal point of said lens.

2. A kit according to claim 1 wherein said second plane is inclined relative to said first plane.

3. A kit according to claim 1 wherein said Fresneltype condensing lens has its axis inclined 5 from the axis of the diffuser 4. A kit according to claim 1 wherein said diffuser has a diameter of about 8 inches to receive and be illuin the directing of traffic.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2484136 *Sep 30, 1947Oct 11, 1949The Union Switch a Signal CompanyCover glass for light signals
US3049614 *Jun 29, 1959Aug 14, 1962Gamewell CoTraffic signal adapter
US3457400 *Aug 10, 1966Jul 22, 1969Minnesota Mining & MfgApparatus and method for directing a beacon toward a limited viewing area
US3597606 *Jan 3, 1969Aug 3, 1971Gen Signal CorpWarning-light housing
US3696715 *Dec 29, 1969Oct 10, 1972Minnesota Mining & MfgBeam defining apparatus
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US5765944 *Feb 4, 1997Jun 16, 1998Fallon; Timothy RossLighting unit that reduces back lighting effects
US6541911 *Feb 4, 2000Apr 1, 2003Matsushita Electric Industrial Co., Ltd.Multi-color emission dispersion type electroluminescence lamp
US6970296 *Nov 12, 2002Nov 29, 2005Osram GmbhSignaling device for traffic signals
US7918588May 2, 2008Apr 5, 2011Musco CorporationFull or near-full cut-off visor for light fixture
US8162511Feb 22, 2011Apr 24, 2012Musco CorporationFull or near-full cut-off visor for light fixture
U.S. Classification362/311.5, 362/311.12
International ClassificationG08G1/095
Cooperative ClassificationG08G1/095
European ClassificationG08G1/095