US1385429A

US1385429A - Searchlight-reflector

Info

Publication number: US1385429A
Application number: US10956A
Authority: US
Inventors: Charles W Crockett; Charles H Crockett
Original assignee: Individual
Current assignee: Individual
Priority date: 1915-02-27
Filing date: 1915-02-27
Publication date: 1921-07-26
Anticipated expiration: 1938-07-26

Description

C. W. AND C. H. CROCKETT SEARCHLIGHT REFLECTOR.

APPLICATION FILED FEH.27, I915- RENEWED JAN-11,1921, 1,385,429.

Patented July 2 H21 wi bhmeo VMW a surface A of a a vertical section thereof and Fig.

jccted forwardly in UNITED STATES PATENT OFFICE.

OF TROY, N'EW' YORK.

SEARGHLlIIGHT-RIJFLECTOR.

Specification of Letters Pa tent.

Patented July 26, 19.21.

Application filed February 27, 1915, Serial No. 10,956. Renewed January 11, 1921. Serial No. 436,615.

To all whom it may concern:

Be it known. that we, CHARLES W. GRocK- m'r' and CHARLES H. CnooKE'IT, citizens of the United States, residing in Troy, liens selaer county, State of. New York, have jointly invented new and useful ments in Scarchlight-Reflectors, of which the following is a specification, reference being had to "the accompanying drawings, in which- Figure 1. shows a diagrammatic representation of our improved reflector; Fig. 2 is IS a front elevation; Fig. 4: shows a section of a modified form of our invention, and Figs. 5, 6, 7, and 8 show diagrammatic reprcsentw ,tions of further modifications thereof.

Our invention relates to scurchllght re flectors, and provides a. reflcctcnparticularly adapted for use in motorvchirlcs, boats and the like, by which the rays of light are pro- :1. direction either parallcl to the horizontal plane through the horizontal axis of the reflector, or down-- wardly, so as to be thrown. (lll't tly into the path of the vehicle or vessel as: t ad "anccs. To this end we construct our scarchlight reflector preferably in the form of a paraboloidal surface or paraboloidal surfaces, with the light so arranged with regard to the focus or tool that all .of the rays of light must be reflected in a direction either parallcl with or downward from the horizontal plane through the horizontal axis of the reflector. Our invention also consists of the construction and cooperation of the parts which we shall hereinafter describe and claim.

Referring to the drawings, and particularly to the form shown in Figs. 1, 2 and 3, (1 indicates a parabolic arc, which, if rotated 180 about a horizontal axis 0, will describe which constitutes the shape of the uaper portion of this form of the reflector. f a point of light is placed above the axis 0. in the vertical plane through the axis, and forward of the line (1, drawn from the focus C to a point on the parabola a which corresprinds to the upperoutcr edge of the reflector, none of the rays of light falling on the surface A will be reflected in an upward direction,

To form the lower portion of the reflcctor, a parabolic arc 7), \aving the same vertex e and axis a as the parabolic are a, is rolace B has Improve also placed paraboloid of revolution,

I tated 180, thereby describing a surface B of a paraboloid of revolution. In order that none of the rays of light reflected from the surface B shall ascend, the parabolic surgreater parameter than the surface A. Hence if a point of light is placed above the axis 0, and in the vertical plane through the axis, and to the rear of the line 7' intersecting tho focus C and extending to a point in the parabolic surface B which cori. ds P. t lower outer edge of the reflector, nonc of he rays of light falling on the surface 13 will be reflected in an upward direction.

It will thus be seen that when the light is placed forward of the line (Z and in the vertical plane of the axis and above the axis, its rays will be reflected by the upper para holic surface A, either parallel to the hori zontal plane through the horizontal axis, or downwardly from the horizontal plane through. the horizontal axis, while, if it is to the rear of the line f and above the axis, and in the same vertical plane as the axis, its rays will be reflected by the lower parabolic surface 13 also either parallel to or downwardl r from the horizontal plane through the horizontal axis. It will also be seen that the horizontal axis 0, with the lines d and f, forms a triangle, as is shown. in Fig. l, the base of which is the axis, and within any part of which the light may be suitably placed, w"1 the re suit that its rays will. be reflects in a direction parallel to the horizontal plane through. the horizontal axis or downwardly therefrom. The extent of the differences of the parabolic surfaces A and B is shown in Fig. 3, but if desired these surfaces may be modified so as to merge into each other, as is shown in Fig. 4.

lVc have observed that in searchlights of the cha actor commonly used, which are usually of a parabolic shapc, the light is normally placed at the focus. If the light were no larger than point, its rays would obviously be reflected hi a direction parallel to the axis, but inasmuch as the light isalways larger than a point, certaino'f its rays are always reflected in directions divergent from the horizontal axis.

We have found in carrying out our invention that there is aspacc whcther the reflector is comprised of one or two parab oloidal surfaccs within which the light may be placed, and that when the light 3. In a searchlight reflector comprising curved surfaces, a space within the reflector the base of which passes through the axis of one of the surfaces and which is forward of a plane intersecting the forward upper edge of the reflector and the focus of an axial vertical section of the upper surface and to the rear of a plane intersecting the forward lower edge of the reflector and the focus of an axial vertical section of the lower surface, and a source of light lying substantially in said space and in the vertical plane of the axes, whereby the reflection of light in one direction is substantially prevented.

4. A Searchlight reflector in the form of one continuous surface without any abrupt break in curvature, in which each half section made by an axial plane is a parabolic are, the focus of the axial vertical upper halt" section and the focus of the axial vertical lower half section being out of coincidence, one of the halves of the reflector hav- :ing axial sections in one portion thereof cliffering in shape from other axial sections in other portions of such half of the reflector.

5. A searchlight reflector in the form of one continuous surface without any abrupt break in curvature, in which each half section made by an axial plane is a parabolic and are, the focus of the axial vertical upper half section and the focus of the axial vertical lower half section being out of coincidence, a source of light lying substantially between the said tool and above the axes of the said vertical half sections, whereby the reflection of light in one diiection is substantially prevented.

6. A searchlight reflector in which the focus of an axial vertical upper half section is out of coincidence with the focus of an axial vertical lower half section, and a source of lightso placed that an axial sec tion thereof is substantially above the axes of the half sections of the reflector and forward of a line intersectin the forward upper end of the upper halt section of the reector and the focus of the axial vertical upper half section, and to the rear of. line intersecting the forward lower end of the lower half section of the reflector and the focus of the axial vertical lower half section, whereby the reflection of light in one direction is substantiall' prevented.

' CHARL S W. CROCKETT.

7 CHARLES H. CROCKETT,

Witnesses:

L. B. Bosrwiox, GEORGE L. MESNIG.