US2007033A - Lighting unit - Google Patents

Description

July 2, 1935. I s, R w A 2,007,033

LIGHTING UNIT Filed Jan. 2, 1952 s Sheets-Sheet 1 Siuarl R. Williams gwgmw ATTORN EY INVENTOR July 2, 1935. s. R. WILLIAMS 2,007,033

LIGHTING UNIT Filed Jan. 2, 1952 5 Sheets-Sheet 2 INVENTOR I I v ATTORNEY Siuari 1i: muwms J 2, 1935- s; R. WILLIAMS 2,007,033

LIGHTING UNIT I Filed Jan; 2, 1952 s sheets-sheet 5 INVENTOR Siuarl 11. Williams ATTORNEY Patented July 2, 1935 2,007,033

UNITED STATES PATENTOFFICE LIGHTING UNIT Stuart R. Williams, Newark, Ohio, assignor to Holophane Company, Inc., New York, N. Y., a corporation of Delaware Application January 2, 1932, Serial No. 584,323

12 Claims. (Cl. 240-25) The present invention relates to lighting units In some forms of street lighting units, the reand is more particularly directed toward lighting fractors employed are open below the light source units having light shields for cutting oli light in so that downwardly directed light is transmitted predetermined directions. without refraction. Where such refractors are In lighting installations employing globes with used, the lighting unit, so far as this direct light 5 or without refractors, (either of symmetric or is concerned, is symmetrical irrespective 'of asymmetric types) there is the possibility that a whether an asymmetric refractor or a symmetric more or less objectionable light beam may be refractor is employed. Some-of this direct light emitted in a direction where it causes glare or a may, therefore, form a beam of objectionable in- 4 bright spot of an objectionable contrasting natensity or make a relatively bright area on the 10 ture. The present invention contemplates prosidewalk. The present invention also contemviding light shields which cut off this objectionplates a light shield preferably secured directly able light, preferably without noticeably altering to the refractor and acting to cut oil? this direct the appearance of the unit when casually observlight through a predetermined angle so as to ing the same. avoid brightly illuminating the adjacent area 15 When controlled street lighting isobtained by oi the side walk. In order to improve the aprei'ractors which direct the light on to the street pearance of the lighted unit and facilitate the surface, diillculties frequently arise on account opening of certain forms of this street lighting of the casting of a beam of light, more or less unit, the portion of light shield below the reintense, in directions where the light is not defractor is curved in vertical planes as well as in 20 sired, as for example, toward buildings along the horizontal planes. side of the street. Variousexpedients have been Other and further objects of the invention will tried to cut oft this undesired light but have been appear as the description proceeds. unsatisfactory on account of the appearance, the The accompanying drawings show, for purpossibility of breakage, the inability to replace in poses of illustrating the present invention, sev- 25 proper position, and difficulty of adjustment. eral embodiments in which the invention may The present invention contemplates a luminair take form, it being understood that the drawmore especially designed for street lighting proings are illustrative of the invention rather than vided with a light shield which effectively cuts limiting the same. In these drawings:

ofi the light in directions where it is not de- Fig. 1 is asectional view more or less diagram- 30 sired, remains in adjustment, d can be ematic through a form of street lighting unit emplaced Whenever necessaryploying an upwardly removable enclosing globe;

Th present invention nt mplat h u Fig. 2 is a section taken on the line 2 2 of Fig. nair wherein the refractor carries an opaque 1 looking i th di ti f th ar o 35 light shield which cuts off the light through a 3 is a View similar to 1 illustrating predetermined angle and prevents the emission form of t et lighting unit employing a pendant of light in predetermined directions. Where the globe; refractor is asymmetri c' the light shield is Fig. 4 is a sectional view with parts in elevaf' placed Q the slde of e e oppo' tion showing an asymmetric refractor open be- 40 slte maX1.mum beam According the low the light source and provided with a light present invention the refractor and shield are controlling Shield, secured together. a mm which. F? be Fig. 5 is a fragmentary sectional view showing replaced and adJusted without any possibility of the Same parts as Fig the shield being improperly placed relative. to E 6 is an inverte'd Ian View of th r f y 40 the refractor. These parts are handled as a t ht hi M 3 e 6 40 unit and the shield may, therefore, be always 2 7 ip p g gioff e ner member properly oriented in the complete unit.

These street lighting units are generally of the refractor showing the light shield in place vided with a slightly difiusing enclosing glass thereon;

globe through which the light from the refractor 3 is a diagram Showing t e Ve t cal disis transmitted. According to the present inventribution of light of the asymmetric d e refraction, the light shield is located in such a manner tor of Fig. 4, with and without the light shield; that while it functions to cut oif light in unde- Fig. 9 is a diagram illustrating the lateral dissired directions, it does not cast an objectionable tribution of light at the angle of maximum disshadow on the enclosing globe. tribution in vertical planes;

Fig. is a vertical sectional view. through a bowl type asymmetric refractor arranged to produce two light beams and provided with a light shield;

Fig. 11 is a sectional view on the line llli of Fig. 10, and

Fig. 12 shows a lighting unit having an outer diffusing bowl and an enclosed light shield.

In the street lighting unit shown in Figs. 1 and 2, the light source is indicated at l0 and a dome type refractor of usual form is indicated at II. It is designed for symmetrical or asymmetrical distribution of light as desired, and is surrounded by an enclosing structure which includes a lower globe 13 made of slightly diffusing glass.

In Fig. 3, the street lighting unit employed has a dome refractor II which may be the same as above referred to and this refractor is housed in an enclosing envelope or globe I4 made of slightly difiusing glassware and hinged to a supporting ring I! as indicated at l 6. This globe may be swung down as indicated in dotted lines to permit access to the lamp and refractor.

The refractor II is made of two annular glass rings 20 and 2| as usual. Where the refractor is asymmetric, it is provided with totally reflecting prisms 22 on its outer surface extending through a predetermined angle, such as 90. The outer glass part 2| is provided with internal prisms and flutes as usual, flutes 23 being placed opposite the reflecting part of the inner glass ring. The inner glass part is provided with a flange 24 around its lower edge and with lugs 25 which normally enter recesses 26 in the inner surface of the outer ring so that the outer ring may be received in proper position on the inner ring. These rings are normally clamped together by metal rings indicated at 21 and 28. A gasket 29 is placed on the flange 24, this gasket having two thicknesses where the light shield, to be referred to, is not present, and a single thickness where the light shield ispresent.

The light shield for use with this form of refractor is made of two pieces of sheet metal. The upper piece is indicated at 30 and the lower piece at 3|. The upper shield piece 30 is shaped to be received between the glass parts 20 and 2 I. It has notches 32 to fit lugs 25 so that the shield will be located back of the totally reflecting prisms. The

stamping 30 has an annular flange-like portion 33 which extends out underneath the lower edge of the outer glass ring 2|. The lower shield member 3| is secured to the upper member 30 by rivets as indicated at 34. This lower member is preferably curved in both horizontal and vertical directions as indicated. It may conveniently approximate a spherical surface and where such a surface is provided it reflects the light beam into the opposite side of the refractor for retransmission thereby. This light shield intercepts a spherical wedge of light.

As will be apparent from Figs. l-3 inclusive, this light shield is close to the light source and spaced a substantial distance from the diffusing globe l3 or H. There is always considerable spillage of light from the refractor and stray light reflected inside the globe so that the globe opposite the shield is dimly illuminated instead of presenting a sharp shadow. Light rays, effective for this purpose, are indicated by lines S in these figures.

By making the lower part 3| of the light shield of the shape indicated, the possibility of casting a marked shadow on the glass is lessened, a minimum amount of material is required, and no interference is offered to the lowering of the pendant globe as indicated in Fig. 3.

Figs. 8 and 9 indicate the light distributions of a unit such as above described, the full line curves indicating light distribution in vertical and lateral directions when the light shield is employed, the dotted lines on the house side of the unit indicating the light which would be projected by the asymmetric unit in the absence of the light shield.

Figs. 10 and 11 indicate the application of the opaque light shield to bowl type refractors closed, or substantially closed at the bottom. The light shield is in the form of an opaque screen 40 interposed between the inner and outer glass parts 4| and 42. The light shield is secured in place when the clamping ring 43 is tightened so that in this construction the light shield is fixedly held in place and this refractor with light shield can be replaced and adjusted as a unit.

In Figs. 10 and 11 the vertical and lateral distributions of the light are illustrated by the dotted curves. It is, of course, understood that the refractor of Figs. 10 and 11 could be enclosed in a globe as usual. 3

In the unit shown in Fig. 12 the shield is indicated at 44. It is inside the slightly diffusing bowl 45, and like the other shields, is shaped to intercept light from the light source above an inclined plane passing through the source and through the boundary line of the street along the ground on the house side of the luminair, so that no direct light falls on the globe above this plane. Scattered light inside the globe illuminates the -globe back of the shield to soften the shadow which would otherwise be cast.

It is obvious that the invention may be embodied in many forms and constructions, and I 'wish it to be understood that the particular forms shown are but a few of the many forms. Various modifications and changes being possible, I do not otherwise limit myself in any way with respect thereto.

What is claimed is:

l. A street lighting unit comprising a light source, an asymmetric refractor about the light source for producing asymmetric longitudinal distribution, an enclosing globe of slightly diffusing glass about the refractor, and a light shield fixedly carried by the refractor for cutting off all light in a predetermined horizontal angle opposite the direction of maximum beam, the light shield being spaced from the globe to permit stray light to illuminate the globe opposite the screen and soften'the shadow which would otherwise be cast by the shield on the globe.

2. In a luminair, a light source, an asymmetric refractor about the light source and comprising two annular glass parts one outside the other, the glass parts having prisms for redirecting light from the light source in predetermined directions and including totally reflecting prisms on the outside surface of the inner ring through a predetermined horizontal angle thereof, and an opaque shield interposed between the glass parts and placed opposite the totally reflecting prisms so that no light is emitted from the refractor in that direction.

3. In a luminair, a light source, an asymmetric refractor about the light source and comprising two annular glass parts one outside the other, the glass parts having prisms for redirectin light from the light source in predetermined directions and including totally reflecting prisms on the outside surface of the inner ring through a predetermined horizontal angle thereof, and an opaque shield interposed between the glass parts and placed opposite the totally reflecting prisms so that no light is emitted from the refractor in that direction, the glass parts and. shield being secured together as a unit so that the unit may be installed in place without disturbing the adjustment of the parts. i

4. In a luminair, a light source, an asymmetric refractor about the light source and comprising two annular glass parts one outside the other, the glass parts having prisms for redirecting light from the light source in predetermined directions and including totally reflecting prisms on the outside surface of the inner ring through a predetermined horizontal angle thereof, and an opaque shield interposed between the glass parts and placed opposite the totally reflecting prisms so that no light is emitted from the refractor in that direction, and a slightly diffusing glass globe outside the refractor and spaced therefrom so that spilled light and stray light within the globe may illuminate the globe opposite the shield to materially reduce the shadow cast on the globe by the shield.

5. In a luminair, a light source, a refractor about the light source and comprising two annular glass parts one outside the other, the glass parts having prisms for redirecting light from the light source in predetermined directions, the refractor being open below the light source so as not to intercept downwardly emitted direct light, and an opaque shield interposed between the glass parts and intercepting the light through a predetermined angle so that no light is emitted from the refractor in that direction, the shield having a downward extension below the glass parts which intercepts a gradually-diminishing area of the direct light through the same horizontal angle as the upper part of the shield and also without intercepting the downwardly emitted direct light.

6. A street lighting unit comprising a light source, an asymmetric refractor about the light source for obtaining a more intense light distributionon the street side of the unit than on the house side, the refractor being made of two parts and openbelow the lightsource so as not to intercept downwardly emitted direct light, a slightly diffusing enclosing globe, and an opaque screen member below the refractor and the house side of the light source to intercept direct light and reflect it toward the street side, the screen member being close to the light source and spaced a substantial distance from the globe to reduce shadow both on the globe and on surrounding areas, the screen member being supported by a portion thereof which extends between the glass parts and intercepts light which would otherwise be transmitted through the outer glass part toward the house side of the unit.

'7. A street lighting unit comprising a light source, an asymmetric refractor about the light source for obtaining a more intense light distribution on the street side of the unit than on the house side, the refractor being open below the light source so as not to intercept downwardly emitted direct light, a globe supporting ring hingedly supported above the refractor on the street side of the unit,a slightly difiusing enclosing globe secured to the ring, and an opaque screen member below the refractor and on the house side of the light source to intercept direct light and reflect it toward the street side, the screen member being curved inwardly to permit the hingedly supported globe to be lowered, and being close to the light source and spaced a substantial disglobe and on surrounding areas.

8. In combination, a light source, an annular refractor intercepting light emitted upwardly from the light source and redirecting it into a downwardly slanting beam, the refractor being 'tance from the globe to reduce shadow both on the open below the light source so as not to intercept downwardly directed direct light, and an opaque screen member extending downwardly from the lower edge of the refractor for intercepting direct light through a predetermined angle and reflecting it toward the refractor for retransmission thereby.

9. In combination, a light source, an annular refractor intercepting light emitted upwardly from "the light source and redirecting it into a downwardly slanting asymmetric beam, the refractor being open below the light source so as not to intercept downwardly emitted direct light, and an opaque screen member on the side of the refractor opposite the maximum beam and extending downwardly from the lower edge of the refractor for intercepting direct light through a predetermined angle and reflecting it in the general direction of the maximum beam.

10. In a street lighting unit, a light source, a refractor above the light source for concentrating upwardly directed light into a downwardly slanting beam, an upwardly opening enclosing globe for the globe refractor, a globe supporting hinge above and to one side of the refractor, the globe being lowered about said hinge to permit access to the lighting unit, and a light intercepting screen below the refractor for cutting oil direct light, the screen being on the side opposite the hinge and close to the light source so as not to interfere with the lowering of the globe. c

11. In combination, an asymmetric refractor comprising two annular glass parts secured together, the inner part having a flange to receive the outer part, the inner part having externally disposed totally reflecting prisms extending about .a portion of its circumference to return the light inwardly,.and an opaque light shield interposed between the glass parts outside the totally refleeting prisms to cut off stray light.

12. In a luminair, a light source, an asymmetric refractor about the light source for altering the light distribution and providing a predetermined asymmetrical distribution in horizontal planes and having a prismatic reflecting Zone opposite the maximum beam of the refractor, and an opaque light shield intercepting light normally emitted through the prismatic reflecting zone.

STUART R. WILLIAMS.

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