US2142467A - Floodlighting unit - Google Patents

Description

Jan. 3, 1939. J. HJWATERBURY FLOODLIGHTiNG UNIT Filed Oct. 9, 1936 R Y m N E V N ATTORNIIEYS Patented Jan. 3, 1939 UNITED STATES PATENT OFFICE.

FLO ODLIGHTING UNIT Application October 9,

1 Claim.

This invention relates to improvements in floodlighting units of a type intended for use in lighting large areas such as sports fields, baseball grounds, and the like.

The principal object of the invention is to provide an improved lighting unit which can be placed relatively far back from the area which is to be lighted and having an improved character of light control and low output loss.

This unit is intended for use with large lamps of from 750 to 1500 watts. It consists essentially of a highly efilcient sheet metal main reflector with a formed sheet metal member mounted therein and acting as an auxiliary reflector to intercept and redirect certain light rays which would otherwise be wasted.

The main reflector is designed tovery definitely control the direction of the reflected rays and to throw a relatively long-range beam of considerable concentration. For sports field lighting it is customary to place units close to or on the boundary lines of theplaying field, but the unit shown and described herein is intended for installation from 60 to 100 feet back of the boundary line. If the auxiliary reflector were not present the beam from the main reflector would be in the shape of a cone with very steep sides and, with the unit pointed toward the playing field for the desired coverage, a considerable amount of light would escape upward in a direction where its usefulness would be lost. The auxiliary reflector intercepts this portion of the cone of light, flattening the top side of the cone and redirecting the intercepted light in a useful direction.

Figure 1 shows the unit principally in vertical section, the section being taken axially with respect to the main reflector and passing through the center of the light source. The upper part 40 of this figure, in elevation, shows the housing for the lamp socket, and means for supporting the unit.

Fig. 2 shows the unit in elevation, as seen from the right in Fig. 1, looking into the open side of 45 the main reflector.

The construction shown in the drawing comprises a housing In which conceals and protects the lamp socket (not shown) and supports the main reflector I I and supplemental reflector I2. The upper part of the housing Ill fits into, and has a detachable connection with, a hood I3, formed with an arm or extension I4 on one side by means of which the unit is supported. This extension has a hinge connection with a mounting bracket I5 by means of a bolt I6 which, when 1936, Serial No. 104,762

tightened, clamps the unit in place after it has been adjusted to the best position for providing the light coverage desired. The extension I4 is formed with a conduit Ma for the passage of the conductor cable to the wiring terminals of the lamp socket. These terminals and the socket itself, as well as the upper part of the lamp, are not shown in the figures.

The main reflector II is provided with an opening which registers with the open lower end of the housing I0 when the reflector is secured to the housing. Bolts I! and I8 secure the reflector in place, these bolts passing through a flange I9 on the housing and a ring 20 within the reflector. A sealing ring 2I of yielding material is interposed between the reflector and the housing to exclude water. The screws l8 also hold in place a bracket 22 which supports the auxiliary reflector I2.

The main reflector is formed with a portion A, from which the light rays are projected forward and slightly downward in a concentrated beam. This reflecting surface is highly polished, then lightly etched to cause the rays to be somewhat diffused. This lightly etched surface, while affording close control of the reflected light, difiuses it just enough to dispel the streaks or striations both direct from the lamp and from the light reflected from the highly polished surface B. B is the portion between the parts A and C of the reflector having a highly polished surface of such contour that the rays reflected from it are directed to the large surface A and redirected forward. The light reflected from portion C is directed substantially in the same direction as from A.

The auxiliary reflector I2 is secured to the bracket 22 by screws 23, 24 and extends forward and slightly downward, relatively to the horizontal, and in a direction substantially parallel to the axis of the main reflector. As seen from the front (as in Fig. 1) this auxiliary reflector is curved downwardly at its ends, and is somewhat wider at its front edge. The rays which strike this auxiliary reflector are directed more nearly downward than the rays from surfaces 0 and A.

It will be seen that the rays which, proceeding from the light source, pass up behind the auxiliary reflector to the surface A of the maini reflector are directed forward and downward, but that the rays which strike the auxiliary reflector would, if the latter were not present, escape upward in a direction where they would have no usefulness.

It is possible to mount this unit on the top of the grandstand or back of the bleachers of a football field and, within the range and width of the beam, to light from one side to the other of the playing field without creating a glare in the faces of the spectators on the opposite side of the field. The beam from the main reflector passes over the heads of the spectators occupying the space between the unit and the playing field, while the auxiliary reflector, in addition to strengthening the illumination of the playing field, directs some of its reflected light to the seating area below, and to a point directly beneath, to relievethe extreme darkness which would otherwise prevail.

Further modifications will be apparent to those skilled in the art and it is desired, therefore, that the invention be limited only by the prior art and the scope of the appended claim.

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

A light unit comprising means for supporting a light source, an annular generally parabolic front reflector in front of said light source for reflecting rays from said light source in a relatively concentrated beam, an intermediate annular reflector in the rear of said front reflector of generally spherical contour for reflecting rays from the light source onto said front reflector, a generally parabolic rear reflector in the rear of said intermediate reflector for reflecting rays from the light source in a generally concentrated beam through said intermediate and front reflectors, and an intercepting reflector in general within said front annular reflector and above the axis thereof for receiving rays from the light source which would otherwise escape in an upward direction and reflecting the received rays downwardly and forwardly, said intercepting reflector being spaced from the axis of said rear reflector far enough so as not to interfere materially with the beam from the rear of the reflector, said intermediate reflector having an opening therein and a hood secured to said intermediate reflector in alignment with said opening for supporting said light source supporting means.

JOHN H. WA'IERBURY.

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