US2167184A - Lighting unit - Google Patents

Description

July 25, 1939. P, 5. PHILLPS 2,167,184

LIGHTING UNIT Filed Dec. 3, 1936 5 Sheets-Sheet 1 4Z zg 34 27 55 l 33 i5, 21' 2f hlx. 7

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July 25, 1939- P. D. PHILLIPS 2,167,184

LIGHTING UNIT Filed Dec. 3, 1936 3 Sheets-Sheet ,2

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P. D. PHILLIPS LIGHTING UNIT July 25, 19,39.

3 Sheets-Sheet 3 Filed Dec. 5, 1956 Patented July 25, 1939 f 2,167,184

UNITED STATES PATENT` OFFICE LIGHTING UNIT Paul D. Phillips, Elmhurst, Ill., assigner to Benjamin Electric Mfg. Company, Des Plaines, ll., a corporation of Illinois Application December 3, 1936, serial No. 113,972

s claims. (o1. 24o-11.2)

This invention relates to lighting units, and might be set, to prevent igniting any material more particularly to portable lighting units` for on this surface in case the lamp is left burning.

use in hazardous locations such as grain elevators Provision is also made whereby'the device may and the like, where the air is dust-laden and likely easily be polarized when desired, to be explosive. Further objects will be apparent from the 5 This application is a continuation in part of specication and the appended calims. my copending application Serial No. 31,960, led In the drawings: July 18, 1935. Figure 1 is a vertical axial section of the unit In certain locations, particularly such as grain and illustrates one embodiment of the invention. elevators, it is desirable that the light source Fig. 2 iS a top plan view of the unit shown in 10 should be completely enclosed to prevent dustV Fig. l with the hood removed, and illustrates the coming in direct contact with hot surfaces, and it method of wiring the fixture.

is also desirable that the structure should be such Fig. 3 is a side elevation of the sealing plug. that all exposed surfaces shall be at a compara- Fig. 4 is a top view of the unit with the hood l5 tively low temperature and that the fixture be so secured thereon. 1L' constructed that no appreciable quantities of dust Fig. 5 is a fragmentary sectional view through will accumulate thereon. one of the wiring terminals, and taken on a line Rubber-covered conductors or cables are usualsubstantially corresponding to line 5 5 of Fig. 2. ly used in Wiring such fixtures, and it is re- Fig. 61s afragmentary axial sectional View ofa quired that these conductors be kept at a com- Slghtly modified embodiment of the DVSIIOII. 20

paratively low temperature, ordinarily not more Fig. '7 is a top view of the embodiment illusthan 120. It is therefore an object to provide a trated in Fig. 6 With the hood removed. xture which may be conveniently installed and Referring to the drawings in detail, the emeasily Wired in such a manner that the rubberbodiment illustrated in Figs. l to 5, inclusive,

covered conductors leading to the terminals are comprises a concave parabolic reflector I which 25 protected from excessive temperatures. may be of polished Nicral or any suitable ma- It is also an object of the present invention to terial, and provided with a cylindrical neck or provide a dust-proof lighting xture having all of extension 2 secured thereto as illustrated, and the above noted desirable characteristics and in arranged to receive the stem of the usual electric which the outer contour is such that excessive bulb 3. The reflector neck 2 is internally flanged 30 quantities of dust will not accumulate thereon. at its upper end as shown, and a socket 4 is A further object is to provide such a unit in secured thereto as illustrated by means of screws which the temperature on the outside of the unit or bolts 5. This socket is preferably a wateris below the charring point of grain dust and the proof molded composition receptacle and is prolike. vided with the usual terminals 6, only one of 35 It is also an object to provide a dust-proof lightwhich is shown, the other terminal being on the ing fixture in which the lamp chamber is sealed opposite side of the socket. An asbestos gasket off from the wiring terminal chamber, and in y'I is secured between the flange of the extension which means is provided to prevent excessive heat 2 and the socket 4, thereby providing a substan- 40 transfer from the light source to the wiring tertially air-tight connection and heat insulation. 40 minals. By means of this construction, the reflector I sur- A further object is to provide such a unit in rounds the bulb portion of the lamp, and is provvhich provision is made for connecting a 3-wire vided with an opening through which the lamp cable, one of which wires affords the ground constem may be inserted upwardly into the socket,

nection, and in which all of the wires leading to and the upper end of the reector is spaced a 45 the terminals are protected from excessive high substantial distance below the lower end of the temperatures. socket by means of the extension 2.

It is also an object to provide a unit of the A sheet metal concave casing 8 surrounds the character described in which provision is made reflector and socket, and is preferably substanfor supporting the unit to enable it to be lowered tially co-axial therewith. 'Ihe lower edge of the 50 into a bin or the like without making use of the casing 8 snugly fits the reflector I, and the reconductor cable as a support. iiector may be secured therein by means of rivets A further object is to provide such a unit in 9, or in any other suitable manner, whereby a which a suitable guard is provided to protect the substantially dust-proof joint is provided.

55' glass front covering from the surface on which it The lower rim of the casing 8 projects out- 55 wardly and is provided with a downwardly-extending flange Iproviding a space between the rim of the reflector I and the flange I0, wherein n may be indented at various points by means of a prick punch to force portions of this flange into the gasket. Y l

A wire guard I6 is secured to the clamping band I3 in any suitable manner, as by welding,

to form an integral part thereof v andto be re-` movable therewith. The casing 8 diverges upwardly away from the reflector to provide a substantial heat-insulation space between the reflector and casing, and also so that the contour may be comparatively smooth and inclined at such a steep angle that dust will tend to slide off the surface and not accumulate thereon. The casing is provided with a restricted portion extending upwardly above the socket 4 and spaced therefrom and provided with an inturned flange An insulating block I8, preferably of wood, is secured to this flange as illustrated, by means of screws I9. Gaskets 20, made of press-board or similar material, are ypreferably inserted be- Y tween the flange I1 and the spacer block I8. The

block I8 is provided with a protecting ferrule 2|, the lower end of which is spaced from the upper end of the casing 8 and secured to the block I8 by rolling the lower edge into a groove `22. The spacing of the ferrule from the casing 8 is to minimize heat transfer therebetween. A comparatively narrow metal strip 23 is secured to the casing 8, preferably by spot-welding, and

YVextends upwardly to overlap the ferrule 2|, and

is retained inV electrical contact therewith byV means of a screw 24. This strip is for the purpose of grounding the entire unit, as will be ex- -plug 29 which is also preferably rmade of wood.

This plug is illustrated in detail in Fig. 3, and is [provided with a flange 30 having a transverse groove 3l therein to receive a wiring cable 32, which is preferably` a S-wire cable. Y

After the unit is filled with insulating material 28as illustrated, the plug 29 is inserted in the Veccentric opening 26 and preferably cemented e therein by any suitable cement, and secured by means Yof Ya screw 33, preferably inserted at the joint as illustrated. The plug is eccentrically positioned in order to provide a narrow wiring space in the depression 21 on the left-hand side as illustrated at 34. The space at Vthis point is just sufiiciently Ylarge to receive the conductors 35,36, and 31, forming a part of the cable 32, and the space gradually increases in width toward the right-hand side of the depression 21 as illustrated, to receive terminals 38 and 3S, as illustrated in Figs. 2 and 5. These terminals are preferably in the form of screws 38 (Fig. 5), secured in the insulating block I8 and provided with openings in their upper end as illustrated, into which the bare ends of the conductors are inserted and soldered. It will be obvious that ordinary binding terminals may be used if desired.

The screws 38 and 39 extend into the chamber 25 of the insulating block I8, and elongated, flexible heat-proof conductors 4!) are electrically secured thereto and to the terminals 6 on the socket 4. These co-nductors il@ are asbestos covered and are entirely within the space between the reflector and casing, and of suflicient length to permit expansion and contraction by changes in temperature, and to prevent their becoming loosened or broken by vibration or shock.

The ground wire 31 is secured to the inturned flange 4I of the ferrule ZI by means of a binder screw 42. It will therefore be seen that after the unit is properly wired, the entire device is suitably grounded. A hood 43 is secured to the insulating block I8 by means of screws 44 extending through the iiange 4I and into the wood block I8. The hood 43 is provided with an upwardly-extending tubular portion 45, through which the conductor cable extends, and which is provided with a suitable packing gland 46. The hood is also provided with a handle or loop 41, by which the fixture may be supported by means of a flexible cable, or in any'other suitable manner, and whereby the fixture will hang substantially vertically when so supported.

It is desirable that fixtures of this type should be polarized in wiring, and therefore the conductors and 36 and the ground wire 31 are preferably of different colors for that purpose. After the fixture has been properly wired, as previously described, a disc 48 is secured to the plug I8 as illustrated in Figs. 1 and 2, by means of screws` 49 extending into the plug. This disc is in a position to clamp the cable 32 in the groove 3l and to clamp the conductorsextending therefrom in the narrow space 34 as illustrated, the conductors extending therefrom to the proper terminals as illustrated.

The upper side of the disc 48 is provided with a diagram and suitable legends such as shown in Fig. 2, which illustrates the manner of wiring in order to suitably polarize thev fixture. This diagram may be stamped or printed directly on the metal disc, or may be printed on a paper or other fabric adhesively secured to the disc.

lIt will be apparent that the construction of the unit is such that dust cannot enter the lamp enclosure, and that the contour of the casing tends to prevent dust from settling thereon. The temperature of the outside of the unit is relatively low because of the insulating material used and o the air spaces between the particles -of insulation.

ing all metallic parts of the unit, and dust is enectively prevented from entering the hood." Provision is also made whereby the unit may be` lowered into a bin or the like without makingV use of the conductor cable as a support, and when the Vunit is placed on the floor the wire guard will support it in upright position and far enough fromV the iloor to prevent danger of igniting the material underneath the lens.

Figs. 6 and 7 illustrate an embodiment of the invention wherein certain parts are omitted, such as the reilector extension neck, and the socket is-mounted directly on a partition between the casing and hood, In this embodiment, the reilector is provided with a central opening 50 to receive the bulb and shock-absorbing springs l are arranged to engage the bulb and lessen the harmful eilects of vibration. The casing 8a is provided with an inwardly-extending flange 52, to which are clamped gaskets 53 and 54, which are held in the position shown, to form an insulating partition by means of screws 55 extending through suitable registering holes in the hood, gaskets, and flange, and threaded into a metal clamping washer 56. The gaskets are provided with registering openings affording access to wiring terminals 51 and 58. A ground terminal 59 is secured to the casing flange and provided with an up-turned portion engaging the hood 6l?. This hood may be similar in construction to that previously described.

In the embodiment illustrated in Fig. 1 it is sometimes desirable to provide an asbestos washer 6| around and snugly fitting the bulb 3. This washer is preferably reinforced by means of a metallic washer 62 secured by means of rivets. The washer is removably held in the extension 2 by means of indentations made in the hood by means of a prick punch.

Further modications 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 claims.

Having thus described this invention, what is claimed and desired to be secured by Letters Patent is:

l. A portable pendant dust-proof floodlighting fixture comprising a lamp socket for supporting a lamp with its axis in substantially vertical position, a concave reflector surrounding the bulb portion of the lamp and having an opening through which the lamp may be inserted upwardly into the socket, the upper end of said reflector being spaced a substantial distance below the lower end of the socket, a lens extending across the light aperture, a metal guard extending across and in front of the lens, a sheet metal concave casing surrounding the reflector and socket and coaxial therewith, a hood above said casing and socket having an opening for the feed wires, a sealing partition between the lamp chamber of the casing and the chamber of the hood having an opening affording access to the wiring terminals of the socket from above, a wiring terminal in said hood for connection with a ground wire electrically connected with said casing, and means for electrically connecting said wiring terminal with the hood comprising a spring clip bearing on the inside of the hood.

2. A portable pendant dust-proof floodlighting fixture comprising a lamp socket for supporting a lamp with its axis in substantially vertical position, a concave reflector surrounding the bulb portion of the lamp and having an opening through which the lamp may be inserted upwardly into the socket, the upper end of said reflector being spaced a substantial distance below the lower end of the socket, a substantially dust-tight enclosure for said socket and reflector comprising a casing and a lens extending across the light aperture, the lower annular edge of the reflector being secured to and supported by the lower annular edge of the'casing, the wall of the casing being coaxial with the reflector and diverging upwardly away from the reflector to provide a substantiall heat insulation space between the reflector and casing, and a substantially dusttight hood detachably secured to said enclosure abo-ve the socket and having an opening for the feed vwires for the socket.

3. A portable pendant dust-proof floodlighting fixture comprising a lamp socket for supporting a lamp with its axis in substantially vertical position, a concave reflector surrounding the bulb portion of the lamp and having an opening through which the lamp may be inserted upwardly into the socket, the upperA end of said reflector being spaced a substantial distance below the lower end of the socket, a substantially dust-tight enclosure for said socket and reflector comprising a casing and a lens extending across the light aperture, the lower annular edge of the reflector being secured to and supported by the lower annular edge of the casing, the wall of the casing being coaxial with the reflector and diverging upwardly away from the reilector to provide a substantial heat insulation space between the reector and casing, a substantially dust-tight,

hood detachably secured to said enclosure above the socket and having an opening for the feed wires for the socket, said lens being convex and extending below the lower edge of the casing, and a metal guard secured tothe lower edge of the casing and having a substantially horizontal portion extending across below the lens for resting on the iloor to support the ilxture in upright position with the convex lens out of contact with the floor.

4. A dust-proof lighting unit comprising a concave reflector, a socket for supporting an electric bulb in axial relation in said reflector, an elongated concave casing surrounding said reilector in axial relation and arranged to form a dust-proof heat-insulating space therebetween, the upper end of said casing being of reduced diameter and having an opening therethrough, an insulating block on said casing and having a passage therethrough forming a continuation of said insulting space through which passage heat insulating material may be inserted into said heat insulating space, said space being substantially completely filled with comminuted heat-insulating material, wiring terminals on said block, a plug sealing said passage and forming a guide for conductors to said terminals, elongated heatproof conductors between said terminals and said socket, and a dust-proof hood on said block and covering said terminals.

5. A dust-proof lighting unit comprising a reflector having a socket for supporting a light bulb, a lens forming a dust-proof cover for said reflector, a sheet metal casing forming an insulating space around said reilector, said casing having a reduced portion extending above said socket and having an inturned flange, a wood block secured to said flange and forming an extension of said insulating space, a ferrule on said block and spaced from said casing but having a comparatively small ground connection therewith, wiring terminals on said block and electrically connected with said socket, a removable dust-proof hood covering said wiring terminals and in grounded relation with said ferrule, and a ground wire terminal connected to said ferrule.

6. A dust-proof lighting unit comprising a reflector having a socket for supporting a light bulb, a lens forming a dust-proof cover for said reflector, a sheet metal casing forming an insulating space around'said reflector, said casing hav- Ying, a reduced portion extending above said socket and having an inturned flange, a wood block secured to said flange and forming an'extension of said insulating space, comminuted heat-insulating material in said space, a ferruleon said block and spaced from said casing but having a comparatively small ground connection therewith,

wiring terminals on said block and electrically connected with said socket, a. removable dustproof hood covering said wiring terminals and in grounded relation with said ferrule, and a ground wire terminal connected tov said ferrule.

7.Y A portable pendant dust-proof floodlighting fixture comprising a lamp socket for supporting a lamp with its axis in substantially vertical position, a concave reflector surrounding the bulb portion of the lamp and having Yan opening through which the lamp may be inserted upwardly into the socket, a substantially dust-tight enclosure for said socket and reflector comprising a casing and a lens extending across the light aperture, theV lower annular edge of the reector being secured toV and supported by the lower annular edge of the casing, the wall of the casing being coaxial with the reflector and diverging upwardly away from the reflector to provide a Vsubstantial heat insulating space between the reilector and casing, said casing having an opening at its upper end, an insulating base extending across said opening and having a passage therethrough through which ,particles of insulating material may be introduced into said heat insulating space, a closure for said passage, wiring terminals on said base, and a substantially dust-tight hood detachably secured to said insulating base and having an opening for the feed;

wires for said terminals.

8. A portable pendant dust-proof oodlighting xture comprising a lamp socket for supporting a lamp with its axis in substantially vertical position, a concave reflector surrounding the bulb portion of the lamp and having an opening through which the lamp may be inserted upwardly into the socket, the upper end of said reector being spaced a substantial distance below the lower end of the socket, a substantially dusttight enclosure for said socket and reflector comprising a casing, a heat insulating block secured to the upper end of the casing and a lensextending across the light aperture, the lower annular edge of the reflector being secured to and sup'- ported by the lower annular edge of the casing, the wall of Vthe casing being coaxial with the reector and diverging upwardly away from the reflector to provide a substantial heat insulation space between the reflector and casing, wiring terminals above said heat insulating block and electrically connected with said socket, and a substantially dust-tight hood detachably secured to said enclosure above the socket and having an opening for the feed wires for the socket. i

PAUL D, PHILLIPS.

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