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Publication numberUS2874270 A
Publication typeGrant
Publication dateFeb 17, 1959
Filing dateJul 12, 1956
Publication numberUS 2874270 A, US 2874270A, US-A-2874270, US2874270 A, US2874270A
InventorsHarry E. Douglass
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Portable work light
US 2874270 A
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Description  (OCR text may contain errors)

Feb. 17, 1959 H. E. DOUGLASS ET AL 2,874,270

PORTABLE WORK LIGHT Filed July 12,, 1956 2 Sheets-Sheet 1 Feb. 17,1959 H. E. DOUGLASS ET AL 2,874,270

PORTABLE WORK LIGHT 2 Sheets-Sheet 2 Filed July 12, 1956 I flame s EDaua IQ Jean/va B. flec'ox INVENTORS.

United States Patent PORTABLE WORK LIGHT Harry E. Douglass, Glendale, and Rodney B. Hecox,

Bakersfield, Calif.

This invention has to do with a portable work light, it being a general object'of the invention to provide a simple and practical explosion-proof light that is safe to use and that is economical-to maintain. This invention is particularly concerned with a fluorescent work light of the elongate tubular type, and provides .for the protection of the tubular lamp that is employed.

In various industries it is necessary to provide portable lighting to be used by the workmen in carrying out their duties. For example, in the construction of aircraft, or in any other construction work, theavailable ambient lighting is inadequate, thus requiring additional lighting in order to see in inclosed places, or in recesses andcompartments, and the like. -In manyinstances the nature of the constructionand the work involved requires an explosion-proof lighting device thatflis of substantial construction so'that the danger of igniting the surrounding and possibly explosive atmosphere isreduced to a minimum. Heretofore, lighting devices ,of the type underconsideration have not been altogether satisfactory since they are generally. vulnerable to breakage, in which event there is likely to be ignition of the surrounding atmosphere. That is, breakage of lightingdevicesof the type under consideration, exposes 'the electrical elements thereof, rendering the devices extremelyfdangerous.

An object of this invention is to provide ap orta ble he 2,874,270 Patented Feb. 17, .1959

e we

fit together on assembly, in order to establish the desired electrical connections and circuitry.

The various objects and featuresof our. invention will be fully understood from the following detailed description of. the typical preferred forms and applications of the invention, throughout which description reference is made to the accompanying drawings, in which:

Fig. 1 is a side view of the portable work light embodying the features of the present invention. Figs. 2 and 3 are enlarged longitudinal section views taken as indicated by lines 2-2.and 3-3 in Figs. 1, respectively. Figs. 4 and 5 are views of parts shown in Fig. 2 of the drawings and showing theparts separate from the inclosing structure. Fig. 6 is an enlarged transverse sectional view taken as indicated by line 6-6 in Fig. 1. Fig. 7-is a transverse sectional view similar to Fig. 6 and showing a modified construction. Fig. 8 is an enlarged transverse sectional view taken as indicated by line 8-8 in Fig. 2. Fig. 9 is a transverse sectional view taken as indicated by line 99 in Fig. 3. Fig. 10 is an enlarged transverse sectional view taken as indicated by line 1010 inFig. ,2. Fig. 11 is an enlarged sectional view taken asindicated by line 11-11 in Fig. 4. Figs. 12 and 13 are enlarged end views of the part shown in Fig. -5, and taken as indicated .by lines 12--12 and 13--13 in Fig. 5. Fig. 14 is an enlarged transverse sectional view taken as indicated by line 14-14 in Fig. 2, andFig. 15 is an enlarged end. view of the starter switch shown in Fig. 2 of the drawings.

The portable work light of the present inventionis a rod shaped illuminating device which may vary'in diameter and length as circumstances require. The structure is particularly adapted to employ fluorescent 1amps,.a'l-: though it will be readily apparent that it is useful in connection with any shape and type of lamp by simply proportioning the structure as required. vAs illustrated, and

. as hereinafterdescribed, we prefer to proportion the work light that is of such construction as to be explosion 1 proof, even under abnormal working conditions. That is,

the light that we provide is so constructed as tobe extremely durable: and not subject to breakage-thus eliminat.-

ing the danger of exposed electrical elements and possible ignition of the surrounding and possibly explosive atmosphere. i

It is an object ofthis invention to provide a portable work light that houses the illuminating lamp in ;achamber that is sealed from the outside atmosphere. The assembly of parts that we provide completely incloses the lamp in a chambenthere being seals at the closures of the chamber that insure positive isolation of the lamp from the surrounding atmosphere. a q Anotherobject of this invention to provide a portable work light of the type. under consideration that includes means for receiving and relating a starter'switchto the other electrical elements of the structure, so that the lamp is illuminated by the cur rent supplied through. a cord.

It is still another object of this invention to provide a The power supply means P provides the. electrical current and involves a' cord 10 that enters the base D and a plug portable .work light of the type under consideration that structure for use with a fluorescent lamp which requires the use of a starter switch. i '1. The structure of the present invention, as shown throughout our drawings, involves generally, a lamp A,

a transparent body, 3, a transparent case C,a base D, a cap E, lamp exciting means F including upper and lower receptacles X and Y and a connector Z', lamp starting means G including a-starter switch S and an adapter R, and power supply. means P. The lamp A is an elongate tubular lamp and is carried within the body B. The "case C, surrounds the body and extends between the base D and cap E, the parts being made so that the body B seals with the base and cap. The lamp exciting means F involves the receptacles X and Y that are carried in the cap E and base D respectively, and'involves'the connector Z which electrically joins the receptacles. The lamp starter means G is carried in the base D and joins elec-- trically with the receptacle Y, which involves circuitry that properly relates the electrical elements of the structure.

11 that joins the cord to the circuitry of the structure.

The lamp A that we have illustrated involves an elon-* gate envelope 12' that is-made of transparentmaterial; such as glass or the like, the ends of the envelope being closed by metal fitting 13. In accordance with the usual lamp construction, a pair of spaced parallel pins 14 proiect axially from each fitting 13, there being pairs of pins 14 at each end of the lamp A. Further, the lamp A is filled with a suitable gas and has electrodes coupled with, the pins to the end that the lamp A is illuminated when electrically excited.

, The transparent body B is an elongate cylindrically shaped tubular elebody B is provided to house and pro-. te'ct'the lamp A, which by itself is a fragile part. The

ment, having an inner wall 16 and an outer wall 17. In accordance with the invention, the body B has end faces 18 in planes normal to the-:axis of the structure and in practice ismade of.a.tempered glass having considerable structural strength. The materialithat we prefer toerriploy is Pyrex .which'is heat-treated annealedglass. 'By employing saidmaterialand by forming the body B with substantial wall thickness, as shown,.there is no danger of the structure failing from internal explosion. For example, the'lamp A, if it explodes, will not cause'bursting of the .body B. The "body B is substantially coextensive with the lamp A and the end faces 18 are flat faces that are trued, as by grinding, in order to seal withfa'cings as later described.

.The transparent case C is provided to encase and protect the glass body B, which could possibly'be damaged or broken by a'sharp blow from the exterior of the structure. The case C, like the body B, is an elongate cylindrically shaped tubular element 'having an inner wall 19 and an outer wall' 20. In accordance with the invention, the case C has threaded end portions'21 for coupling the case to the base D and the cap E as later described. In practice,'the case C is made of a so called plastic material that is tough'and shock-resistant. The material that we prefer to employ is .ucite, which is a tough shockwithstanding material. The inner wall 19 of the case slideably receives the outer wall 17 and of the body B, and is coextensive with and surrounds the body B to the end'that the bodyB is protected from external abuse. The'tubular concentricelements B and C encase'and protect the lamp A so that neither external abuse nor internal explosion will cause breakage or failure ofthe body B. Thus the body 'B --maintains a closed protective chamber 22;

The base D andcap E-are provided to close the ends of 'thelbodyB in order to maintain the-said closedchamber '22. The normal operatingposition'of the portable work lightis vertical, in which .case the base D closes the lowerend of the body, while the cap E closes the upper end of the body. The base D is-coupled to the lower end portion of the'case- C, and carries parts of the lamp exciting means F, and also carries the lamp starting means G.

The base D is a cylindrical element that is joined to the lower end of the case C by means of a coupler 23 to depend from the lower end of the body and-case assembly. As-best illustrated in'Fig. 2 of the drawings, the base D involves an elongate vertically disposed shell 24'and the coupler 23.forms an upwardcontinuation of the shell. A bore 25 enters the lowerend ofthe shell 24 to receive elements of the powersupply means P, while a counterbore.26, larger in diameter thanbore 25, enters the upper end of the shell 24 to receive the lamp starting means G. There is an upwardly faced shoulder 27 where the bore 25.,and counterbore 26 adjoin.

The-coupler 23 is releasably connected to the shell 24 by means of threads 23' and has an inner bore 28 larger in diameter than the counterbore 26 to receive the receptacle Y of the means F. The shell terminates in an upper end face 29 in a plane normal to the vertical axis of the structure, thus forming a seat for supporting the receptacle'Y. Asshown, the coupler .23 has internalthreads 30 at the upper end portion thereof, somewhat smaller in diameter than the bore 28. The threads 30 couple with the threaded lower end portion 21 of the case C, and being smaller in diameter than the bore recetpacle Y in working position.

The cap E is a closure element that is joined to the upper end of the case C to overlie the upper. end of the body and case assembly. As best illustrated in Fig. 3 of the drawings, the cap E involves an-inverted cup shaped part 33 that has a bore 34 with a bottom 35. The part 33 is releasablyconnected to the caseC and as shown, the bore has internal threads that couple with the threaded upper end portion 21 of the case C.

28, retain the The bottom 35 of the part 33 is a plane normal to the axis of the structure and, in accordance with'the invention, is provided with a facing 36 adapted to seal with the upper end face 18 of the body B. In practice the facing 36 may be a layer of lead, or the like, that will seal tight with the end face 18. As shown, the facing 36 may be a disc shaped facing co-extensive with the bottom 35. Further, the cap B may include means for supporting the portable work light that we provide,-and as illustrated in Figs. 1 and 3 of. the drawings, there is provided a swivelly mounted suspension hook 37. 'The hook 37 is rotatably carried by the part 33 and projects upwardly therefrom for engagement with a supporting object or structure.

It will be apparent from the foregoing and from Figs. 2 and 3 of the drawings, that the base'D and cap E close the ends of the body B and .case C, forming the closed chamber 22 in the body. In carrying out the invention, the case C is made slightly shorter than the body B, so that the ends'18 of the body are'broughtinto contact with the seals, as shown. It will be understood how the cap E and coupler 23 are rotated relative to the case C in order to create a'tight seal 'at the ends 18 of the body B.

The lamp exciting means F is provided to electrically connect the lamp A with the power supply means P, and with the lamp starting means G when employed. As shown throughout the drawings, the means F involves generally the upper and lower receptacles 'X and Y and the connector Z that extends between the receptacles. When employing a fluorescent type lamp A, it is necessary to electrically excite both the upper and lower ends of the lamp, and it is also necessary to make provisions for a starting circuit. The means F that we have illustrated'incorporates features adapted to handle a fluorescent lamp and therefore includes means to excite both ends of the lamp and also includes a starting circuit; I}

The upper receptacle X of the means F is best illustrated in Figs. '3 and 9 of the drawings, and involves a body 40, a pair of lamp'contacts41 and 42, and a pair of connector contacts 43 and 44. The body 40 is made of insulating or dielectric material and is shaped to enter into the upper end of the body B. The body 40 has an outer wall 45 that is slideably received in the inner wall 16 of the body B and has bearing engagement with the facing 36.

The lamp contacts '41 and 42 are spaced parallel pin receiving'contacts that are carried in the body 40 and are axially disposed to receive the pins 14 that project from the upper end of 'the lamp A. The connector engaging contacts 43 and 44 are also spaced parallel pin receiving contacts that are carried in the body '40 and are positioned laterally to one side of the contacts and 42 to receive pins that project from the connector hereinafter described. The contacts '41 and 42, and the contacts 43 and 44, are spring type contacts that frictionally engage with the pins that are received therein. As shown-in Fig. 9, the contacts 41 and 43 are joined by a bar 47 while the contacts 42 and are joined by a bar 48. The elements of the receptacle X are accommodated in suitable recesses in the body 40 and are held in place by an insulating cover 49.

The lower receptacle Y of the means F is best illustrated in Figs. 2, 4, 8, 10, and 11 of the drawings and involves a body 50, a pair of lamp contacts 51 and 52, a pair of connector contacts 53 and'54, a pair of power contacts, 55 and '56, and a pair of and 58. The body '50 is made-of insulating or dielectric;material and-is shaped to enter into the bore '28 in the coupler 23. The body 50 has an outer wall 50that is slideably received inthebore 28 and has a flat lower end 60 thathas bearingengagement with the upper end face 29 0f the shell 24. Inthe preferred form of the invention, the body 50 has aflat upperend 61.in.a.plane normal to the axisof the structure and in accordance with .thezinvention, is provided with a facing 62 adapted starter contacts, 57

I type to seal with thelower endface, 18 of the body B. In

practice the facing 62 may be a layer of lead, or the like, that will seal tight with,the end face 18. 'As shown, the facing'62 may be a ring shaped facing inserted into the periphery of the upper end 61 of the body 50. It will be apparent how the facings 36 and 62 seal with the end faces 18 to close the chamber 22 within the body B. I

The pairs of .contacts above referred to are carried in the body 50, the contacts 51 and 52, and contacts 53 and 54 being located at the upper end 61 of the body, while the contacts 55 and 56, and contacts 57 and 58 are located atthe lower end 60 of the body.. In the preferred construction the body 50 is a sectional unit of construction made up of upper and lower disc shaped elements 63 and 64, suitably held together by fasteners or the like. We have-shown screws 64 carried in ele:

ment 64 threaded into openings in the. element 63. The,

element 63 carries the upper contacts that engage with the lamp A and connector Z, while the element 64 carries the lower contacts that engage with the powersupply means P and the starter switch S. There are bars later described that electrically connect the contacts, the contacts and bars being carried in recesses in one of the disc shaped elements. ,We have shown recesses in the lower element 64 that accommodate said bars. The lamp contacts 51 and 52 are. spaced parallel pin receiving contacts that are carried in the upper element 63 of the body 50 and are axially disposed to receive the pins 14 that project from the lower end of the. lamp A. The connector engaging contactsv 53 and 54 are also spaced parallel pin receiving contacts that are carried in the upper element 63 of the body 50 and are positioned laterally to one side of the-contacts 51 and 52 and are axially disposed to receive pins that project from the connector hereinafter described.1 The contacts 51 and 52, and contacts 53 and 54 are spring contacts thatfrictionally engage with pins that are received therein. As shown in Fig. 11, the contacts 51 and 55 are joined by abar 65, while the contacts 52 and 57 are joined by a bar 66. The contacts 53. and 56 are joined by a bar joined by a bar 68; The contacts 57 and 58-are. spaced parallel pin receiving contacts that .are carried in the lower element 64 f thebod y 50 and are'disposed axially to receive pin contacts later described. I The contacts 55 and 56 are pin type contacts that project axially of and depend from the lower end 60 of the body 50. j

The contacts 41 and 42, and contacts 51 and 52 are located approximately centrally of the structure so that the lamp A is substantially centered with the longitudinal axis of the structure. In practice, however, the said contacts are located somewhat oif-center in .order to gain room for the connectonZ that occupies the chamber 22 later-ally of and to one side of the lamp A. The connector Z extends between the receptacles X and Y and involves a shield 70 and a pair of busses 71 and 72 that join the connector contacts of the receptacle. The busses 71 and 72 are elongate rod like elements with pin like projections at the ends thereof that are carried in a spaced parallel relationship by the elongate shield 70.

The buss 71 extends between and has pin shaped end portions that connect with the contacts 43 and 53, while the buss 72 extends between and has pin shaped end portions that releasably join with the contacts 44 and 54.

In Figs. 2, 3, and 6 of the drawings, the shield 70 is shown of minimum cross section and formed of a transparent material so that light may pass therethrough with the least amount of obstruction, in which case the busses are the only obstruction. In Fig. 7 we have shown a modified construction wherein the connector Z involves an elongate shield 70' is of substantial width in cross section. In the latter form of the invention, the shield 67, while the contacts 54 and 56 are entially of the lamp A to substantially cover one side 6 thereof. The outer wall 74 of the .shield 70 isicurved to fit within the wall16 of the body B, and the inner wall 75 iscurved 'to act as a' reflector and may be suit-" ably coated with a layer of reflecting material, as circumstances require. It will beapparent how the connector Z joins the receptacles X and Y and acts as a shield and/ or a reflector when desired.

The lamp starting means G is preferably carried within the base D and joins electrically with the receptacle Y and involves a starter switch 76. The counterbore 26 in the base B is provided to receive and accommodate the starter switch 76, the switch having pins 77 and 78 that are releasably engaged in the contacts 57 and 58 respectively. We have shown a common ordinary starter switch 76 that is contained in an elongate cylin drical container and which involves the pins 77 and 78 that project upwardly from the top 79 of the container, which container has an outer wall 80 and a bottom 81. The wall 80 is received in the bore 26 with clearance and the bottom 81 is positioned by the shoulder 27 so that the pins 77 and 78 extend into engagement with the contacts 57 and 58. It will be apparent how the starter switch 76 is electrically related to the power means P and lamp means A through the relationship of contacts and bars above described.

The power supply means P is provided to energize the electrical circuit and lamp A and conducts electrical current from the cord 10 through the plug 11 and to the pin contacts 55 and 56. The means P involves the is necessary. However, if the starter switch 76 is to be.

carried remote from the portable work light structure, a four line circuit will be necessary. In the .case illustrated, the adapter R is a cup shaped sleeve like part slideably carried and seatedon the shoulder '27 in the bore 26, and is provided with a socket or recess 86 that slideably receives the starter switch 76 to hold it in working position. recessed and carries a pair of pins 87 and 88 that engage with the plug 11. Conductor bars 89 and 90 extend from the pins 87 and 88 to pin receiving cont-acts 91 and 92 that are located in the top end of the adapter 6 R. The conductor bars 89 and 90 are carried in longitudinal recesses in the side wall of the sleeve. The contacts 91 and 92 engage with the contacts 55 and 56, above described. Included in the power supply means P is a transformer (not shown) that delivers the proper voltage for operation of the particular lamp A that is employed. The power supply means further includes means for anchoring and for sealing around the cord 10. As shown, a resilient gland 95 is provided that yieldingly grips the exterior of the cord 10. The lower end portion of the bore 25, in the base D, is tapered and the gland 95 is shaped to substantially fit the tapered portion of said bore. The gland 95 is in the nature of a sleeve of resilient rubber like material and has an enlargement that is engaged by a screw cap 96 threaded on to the lower end of the base D. It will be apparent how operation of the screw cap 96 acts to compress the enlargement on the gland 95 to seal and grip the cord 10.

From the foregoing it will be apparent that we have provided a relatively simple and extremely durable port able work light of the type under consideration. The lamp A is not only protected from blows from the exterior of the structure, but is isolated within a closed chamber. With the structure that we provide, the chamber is positively sealed at the ends thereof, and the transparent body which form the chamber is protected by being inclosed within a case of shock resistant material. It is to be observed that the ends of the shock As shown The bottom 85 of the adapter R is.

resistant-case are-coupled tothe base. and cap of the structure, respectively, and when the structure isassembled, the bodyB is put under direct compression, insuringa tight seal at the facings 36 and 62. Further, it is to bev observed that theelectrical elements are characterized by receptacle type elements and pins that are engaged therein to the end that assembly of the structure is facilitated. That is, the parts and elements of the structure'are merely pressed together, and when the case C is coupledbetween the base D and cap E, the structure is ready for operation.

Having'described only typical preferred forms and applicationsof our invention, we do not wish to be limited or restricted to the specific details herein set forth, butwish to reserve to ourselves. any variations or modifications that may appear to those skilled in the art and fallwithin thescope of the following claims.

"Having described our invention, we claim:

1. A Work light of the character described, including, an elongate tubular body, a base of insulating material closing one end of the body, a cap closing the other end of the body, an elongate lamp carried within the body, there being a bore in the body, and lamp exciting means including, receptacles releasably engaged with opposite ends of the lamp, each receptacle having a pair of lamp contacts and a pair of contacts laterally ofiset therefrom, one of the receptacles havinga pair ofstarter contacts, a. connector extending between the receptacles and releasably engaged with said offset contacts, a cylindrical adapter of insulating material carried in the bore in the base, and a starter switch slideably received in the adapter and releasably engaged with said starter contacts, there being electrical conductors carried between the bore and adapter and connected with a power supply and connected with the receptacle having the starter contacts.

2. A Work light of the character described, including, an elongate tubular body, a base of insulating material closing one end of the body, a-cap closing the other end of the body, an elongate lamp carried within the body, there being a bore in the body, and lamp exciting means including receptacles releasably engaged with opposite ends of the lamp, each receptacle having a pair of lamp contacts and pair of contacts laterally offset therefrom, one of the receptacles having a pair of starter contacts, a connector extending between the receptacles and releasably engaged with said offset contacts, a cylindrical adapter of insulating material carried in the bore in the base, and a starter switch slideably received in the adapter and releasably engaged with said starter contacts, there being elongate electrical conductors coextensive with the adapter and carried between the bore and adapter, and a plug connected with a power supply,

said electrical conductors-having terminal ends adapted terial, a base closing the body and case at one end, a-

cap closing the body and case atthe other end, an elongate lampcarried in the body and with terminal end fittings and each having an electrical contact, and electrical-means exciting the lamp at said base and cap, and including, a receptacle with an electrical terminal engaged with a contact at one end of the-lampand supported by a shoulder in the base, an axially disposed facing of sealing material on said'rcceptaclc, a receptacle with an electrical terminal engaged with a contact at the other end of the lamp, and a connector extending between the receptacles, anaxially disposed facing in the cap, said case being engaged with the base and cap and under tension to hold the bodyunder pressure between the facings and sealedtherewith.

4. A work light of the character described, including, an elongate tubular body of transparent high strength material, a tubular-casecoextensive with and surrounding the body and oftransparent shock resistant material,- a base closing the body and coupled-to the case at one end, a cap closing the body and coupled to the case at the other end, an elongate lamp carried in the body and with terminal end fittings and each having an electrical contact, and electrical. means exciting the lamp at said base and cap, and including, a receptacle with an electrical terminal engaged with a contact at one end of the lamp and supported by a shoulder in the base, an axially disposed facing of sealing material on said receptacle, a receptacle with an electrical terminal engaged with a contact at the other end of the lamp, and a connector extending between the receptacles, an axially disposed facing in-the cap, said case beingengaged with the base and'cap and under tension to hold the body under pressurebetween the facings and sealed therewith.

References Cited in the file of this patent UNITED STATESPATENTS

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