US3702931A

US3702931A - Device made from insulating material for electrical insulation of a switch in a work-lamp shield

Info

Publication number: US3702931A
Application number: US213376A
Authority: US
Inventors: Jac Jacobsen
Original assignee: Jac Jacobsen AS
Current assignee: Jac Jacobsen AS
Priority date: 1971-12-29
Filing date: 1971-12-29
Publication date: 1972-11-14
Anticipated expiration: 1989-11-14

Abstract

A work lamp has an insulated housing within a shade which encloses the switch and the terminals for the electric cable connected to the switch. The insulated housing is formed of an electrical insulating material and defines a closed insulated chamber in which the switch is mounted. The enclosure has an elongated extension forming an insulated conduit for the electrical cable passing through the lamp''s shade to the switch in the insulated chamber. The extension has a free end portion located in an opening the lamp shade and the free end portion has at least two closely adjacent spaced edges clamping the electrical cable in a relatively fixed position therebetween.

Description

United States Patent J acobsen DEVICE MADE FROM INSULATING MATERIAL FOR ELECTRICAL INSULATION OF A SWITCH IN A WORK-LAMP SHIELD [72] Inventor: Jac. Jacobsen, Oslo, Norway [73] Assignee: Jae. Jacobsen A/S, Oslo, Norway [22] Filed: Dec. 29, 1971 21 Appl. No.: 213,376

A Related US. Application Data [63] Continuation-impart of Ser. No. 107,358, Jan.

18, 1971, abandoned.

[52] US. Cl ..240/122, 174/52 R, 174/138 F, 200/168 C, 240/112 R, 240/6l.1l

[51] Int. Cl. ..F2lv 23/04, F21] 15/00, HOlh 9/02 [58] Field of Search ..174/50, 52 R, 65 R, 138 F; 200/168 C; 240/2 S, 11.2 R, 11.2 E, 11.3, 52

R, 52 BL, 61.11, 81 P, 122, 153; 339/107 [56] References Cited UNITED STATES PATENTS 3,534,150 10/1970 Kudlaty .,.....174/l38F .30 g i I 6 l 5] Nov. 14, 1972 Primary Examiner-Laramie E. Askin A ttomeyl-larold l... Stults [57] ABSTRACT A work lamp has an insulated housing within a shade which encloses the switch and the terminals for the electric cable connected to the switch. The insulated housing is formed of an electrical insulating material and defines a closed insulated chamber in which the switch is mounted. The enclosure has an elongated, extension forming an insulated conduit for the electrical cable passing through the lamps shade to the switch in the insulated chamber. The extension has a free end portionlocated in an opening the lamp shade and the free end portion has at least two closely adjacent spaced edges clamping the electrical cable in a relatively fixed position therebetween.

17 Claims, 6 Drawing Figures DEVICE MADE FROM INSULATING MATERIAL FOR ELECTRICAL INSULATION OF A SWITCH IN A WORK-LAMP SHIELD This application is a continuation-in-part of my copending US. Pat. application Ser. No. 107,358, filed on Jan. 18, 1971, now abandoned, the disclosure of which is incorporated herein by reference.

This invention relates to lamp structures and more particularly to an enclosure for a lamp switch and electrical cable therefor which is formed of an electrical insulating material that provides insulation between the components of the lamp circuit and also between them and the metallic lamp shade and other exposed conductive lamp components.

Safety standards for electrical appliances have recently become increasingly more strict as an effort is being made to eliminate all electrical hazards associated with such appliances. One such hazard occurs wherein a lamp bulb socket and switch are located within a metallic lamp shade. The hazards which may occur with such an arrangement involve one or more of the following: contact of conductive portions of the switch with the lamp shade, fraying of the lamp cord or electric cable at the point of passage through the lamp shade, and loosening of the cord from the switch by pulling forces exerted on the lamp cord. One suggested manner of avoiding these hazards is to doubly insulate both the switch and the electrical cable from the lamp shade while providing a pull lock for the electrical cable to prevent it from being pulled from the switch.

It is an object of the present invention to eliminate the above-mentioned potential electrical hazards associated with the use of lamps having a metallic shade by an insulating and cable locking system which is relatively simple and inexpensive to manufacture.

Another object of the present invention is to insulate the two sides of the electrical circuit in a lamp arrangement from each other and also from the exposed conductive parts of the lamp.

Yet another object of I the present invention is to prevent wear or fraying of the electrical cord at the point wherein it enters the lamp shade.

A still further object of the present invention is t prevent damage which could be caused by tension on the cordswitch connection.

In accordance with one aspect of the present invention, a device for insulating a switch in a lamp and for insulating and locking the electrical cable passing through the lamp shade to the switch is provided in which a switch enclosure is formed by an electrical insulating material. The enclosure is constructed from a generally circular base member having a peripheral wall extending upwardly therefrom, which has a free edge remote from the base and an arcuate opening therein. A generally circular lid is positioned in engagement with the free edge portion of the wall about its periphery and has an arcuate wall portion extending therefrom, which wall portion is complementary to and received in the arcuate opening of the peripheral base wall in order to maintain the base and lid in a predetermined relative position. The base and lid define therebetween an enclosed insulated chamber in which the switch is mounted so that it is isolated from the lamp shade and from the light socket portion of the cirsuit. The base and lid members have cooperating elongated extensions defining an insulated conduit for the electrical cable, which extensions extend respectively from the arcuate opening and the arcuate wall in said base and lid members, to the free ends thereof. These free ends are located in adjacent spaced relation in an opening in the lamp shade to clamp the electrical cable therebetween in order to prevent movement of the cable with respect to the lamp shade and to lock the cable in a fixed position with respect to the switch, thereby avoiding fraying of the electrical cable and assuring that it cannot be pulled out of the switch.

The above, and other objects, features and advantages of the present invention will be apparent in the following detailed description of an illustrative embodiment thereof, which is to be read in connection with the accompanying drawings wherein:

FIG. 1 is a sectional view of a base member, constructed in accordance with the present invention, forming a part of the insulating enclosure for a lamp switch and the electrical cable therefor;

FIG. 2 is a plan view taken in the direction of the arrows 2-2 of FIG. 1;

FIG. 3 is an elevational view of the lid member which cooperates with the base member illustrated in FIG. 1 to form the switch enclosure;

FIG. 4 is an end view of the lid member taken in the direction of the arrows 44 of FIG. 3;

FIG. 5 is an enlarged sectional view of the switch and cable enclosure, constructed in accordance with the present invention, in its assembled position, as mounted in a lamp shade; and

FIG. 6 is a partial perspective view, of the apparatus of the present invention mounted in a completed lamp assembly, with a portion of the lamp shade thereof broken away.

Referring now to the drawings in detail, and initially to FIGS. 5 and 6 thereof, it will be seen that the insulated switch enclosure and cable locking apparatus E, embodying the present invention, as shown therein, is mounted by a bracket 17, as more fully described hereinafter, in the interior of a metallic light shade 16. The latter is rotatably mounted by 'a stem 19 in a bracket 21 on a well known light stand assembly during use. A light bulb socket 22 is also mounted on bracket 17 and is electrically connected to a switch 12 contained within the enclosure E.

Enclosure E is constructed from two

mating enclosure members

1 and 6, both of which are formed from an electrical insulating material. Enclosure member 1 comprises a generally circular base 3 having an arcuate wall 2 about substantially its entire periphery, but which has an arcuate opening 23 formed in wall 2 between the

edges

24, 25 thereof. Enclosure member 6 is formed as a generally circular lid which is adapted to engage and rest upon the free edge 26 of peripheral wall 2 of enclosure member 1 so as to define a switch enclosure chamber 26' therebetween (FIG. 5). Lid 6 also includes an annular ridge 14 adjacent its annular edge but spaced inwardly thereof, which ridge provides an inner guide ring that abuts against the inside of peripheral wall 2 to prevent inadvertent dislocation of the two parts with respect to each other. In addition, lid 6 includes a pair of arcuate wall segments 27 which together define an arcuate wall whose arcuate length between the edges 28 thereof is substantially equal to the distance between the

edges

24, 25 of arcuate opening 23. The wall provided by arcuate segments 27 fits within and between

edges

24 and 25 of wall 2, in the assembled configuration of the device, and serves to maintain lid 6 and base member 3 in a predetermined relation with respect to each other.

The inner surface 29 of lid 6 is provided with a pair of spaced tabs 30 (only one of which is seen in FIGS. 3 and which serve to frictionally engage switch 12 therebetween and hold it in a relatively fixed position on the lid. These tabs also prevent inadvertent rotation of the switch during use of the lamp.

In assembling the apparatus of the present invention, switch 12 is placed between tabs 30, on lid 6, and base member 1 is placed in position against lid 6 with arcuate wall member 27 located in an opening 23 and ridge l4 engaged with the interior of wall 2.

In order to maintain

enclosure members

1 and 6 in a fixed position with respect to each other, base 3 is provided with an elongated tongue 31 having an enlarged head portion 9, in the shape of an arrow as seen in FIG. 1. Preferably, tongue 31 is located opposite opening 23 adjacent a break 31' in wall 2. On the other hand, lid 6 is provided with a generally rectangularly shaped opening 13 therein which is complementary to and receives head portion 9 of tongue 31, which head portion is snap fit in aperture 13 with the shoulder 33 thereof engaged with the surface of lid member 6 to retain the lid in fixed position with respect to enclosure member 1.

Lid 6 further includes an elongated arm or extension 7, which is generally U-shaped in cross-section, as seen in FIG. 4, to define a conduit or channel 32 between the leg portions 7 thereof. Similarly, enclosure member 1 includes a complementary, but generally flat arm 4 which, in the assembled configuration of the apparatus, engages the free edges 34 of channel 7 to enclose conduit 32 and thereby form an enclosed insulated conduit for the electrical cable (FIG. 5) between the interior of chamber 26 and the exterior of lamp shade 16. This arrangement permits cable 15 to be connected at one end to switch 12 and extend through shade 16 so that its other end (not shown) can be connected to a source of electrical current.

Arm 4 extends substantially at right angles to the plane of the base 3 of enclosure member 1 and is located intermediate the ends of opening 23 in wall 2. The free end 5 of arm 4, as seen in FIG. 1, extends substantially at right angles to member 4 and has a serrated bent-over edge portion 38. Similarly, arm 7 of lid 6 extends substantially at right angles to the plane of the lid, and has an enlarged free end portion 8 extending at right angles thereto. Free end 8 of arm 7 is also generally U-shaped, as seen in FIG. 4, and defines a serrated edge portion 39 which cooperates with serrated edge 38, in the completed configuration of the apparatus shown in FIG. 5, so as to grip the electrical cable 15 therebetween and lock it in a relatively fixed position. The free ends 38 and 39 of arm members 4 and 7 are positioned within an aperture 44 formed in the periphery of the metal lamp shade 16, and serve to prevent movement or rubbing of the cable against the metal lamp shade 16 so that fraying is avoided. In addition, by locking the cable in a fixed position at this point, it is made relatively impossible to pull the cable from the switch 12, thereby avoiding possible short circuits in the lamp.

Lid 6 also further includes a central aperture 11 through which the push button operating stem 40 of switch 12 passes to the exterior of the lamp shade 16 through an opening 20 therein in order that the switch may be manually operated. On the other hand, the base 3 of enclosure element 1 includes a pair of locking plungers 10 which are snap fit within openings 41 formed in the end 42 of bracket 17, in order to mount enclosure E on the bracket. Locking plungers 10 are hollow members through which the leads 43 from switch 12 pass to socket 22, also mounted on bracket 17, in order to supply electrical current to the socket for operation of a bulb placed therein.

In addition, base member 3 is provided with two or more equally spaced supporting pads 45 which maintain the base member in a fixed spaced position with respect to the metal bracket 17 and add rigidity to the entire housing structure as it is mounted within the shade l6. Bracket 17 is secured to shade 16 by a conventional nut and bolt arrangement on stem 19 and, in this manner, the entire assembly of lamp socket and insulated switch enclosure are simultaneously mounted in fixed position on the lamp shade. I

It is thus seen that a relatively simple and inexpensively manufactured insulating enclosure is provided which performs a plurality of functions in regard to the prevention of safety hazards with lamp constructions having metal lamp shades. In particular, the enclosure E provides an insulated enclosure for the switch assembly 12 which isolates the switch from the metal enclosure and also from the bracket 17 and socket 22 so that there can be no conductive contact therebetween. Moreover, enclosure E simultaneously provides an insulated conduit 32 for the electrical cable which supplies current to the switch and lamp socket. This is achieved by extension arms 4 and 7 of the

enclosure components

1 and 6 respectively. Since these extensions are provided with serrated

free edges

38, 39, which are located in closely spacedv relation to each other and held in that closely spaced relation because of the close fit and constant mating of the

members

1 and 6 as maintained by the tongue 31, they grip the cable 15 tightly therebetween and prevent, it from being pulled from the switch or moved with respect to the lamp shade.

Although an illustrative embodiment of the present invention has been described herein with reference to the accompanying drawings, it is to be understood that that invention is not limited to that precise embodiment and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of this invention.

What is claimed is:

1. A device for insulating a switch in a lamp and for insulating and locking an electrical cable passing through the lamps shade to the switch, said device comprising an enclosure formed of an electrical insulating material and defining an enclosed insulated chamber in which said switch is mounted, said enclosure having an elongated extension forming an insulated conduit for the electrical cable passing through the lamps shade to the switch in said chamber, said extension having a free end portion located in an opening in said lamp shade and said free end portion having at least two closely adjacent spaced edges clamping said electrical cable in a relatively fixed position therebetween.

2. A device as defined in claim 1 wherein said enclosure is formed of first and second insulation members interconnected in mating relation to define said enclosed insulated chamber, with each of said insulation members having an elongated arm located adjacent to the arm on the other of said members and cooperating therewith to form said insulated conduit.

3. A device as defined in claim 2 wherein said first insulation member includes a generally circular base portion and a peripheral wall extending upwardly from said base portion, said wall having a free edge portion remote from said base portion.

4. A device as defined in claim 3 wherein said second insulation member comprises a generally circular lid engaged with said free edge portion and cooperating with said base portion and peripheral wall to form said insulated chamber, and means maintaining said first and second insulating members in a predetermined relative position.

5. A device as defined in claim 4 wherein said peripheral wall has an arcuate opening therein and said means maintaining said first and second insulating members in a predetermined relative position comprises a generally arcuate wall member extending from the periphery of said lid towards said base portion, said arcuate wall having an arcuate distance between its ends substantially equal to the arcuate length of said opening, said arcuate wall being received in said opening to maintain said first and second insulating members in a predetermined relative position.

6. A device as defined in claim 5 wherein said elongated arms are respectively located in mating relation adjacent said opening in saidperipheral wall and adjacent said arcuate wall, with one of said arms being generally flat and the other of said arms being generally U-shaped in cross-section, said flat arm engaging the free edge of said U-shaped arm to form said insulated conduit therebetween.

7. A device as defined in claim 6 wherein said arm members each includes cooperating secondary members extending substantially at right angles to said arms and being located in said opening in the lamp shade, said secondary members defining said free edge portions of said elongated extension and forming said closely adjacent spaced edges.

8. A device as defined in claim 7 wherein said closely adjacent spaced edges are serrated.

9. A device as defined in claim 7 including means maintaining said first and second insulating members in mating relation.

10. A device as defined in claim 9 wherein said lastmentioned means comprises an aperture in one of said lid and base portion and an elongated tongue member peripheral wall extendin upwardl therefrom, said wall having a free edge an an arcua e opening therein;

a generally circular lid member engaging said free edge about its periphery and having one arcuate wall portion extending therefrom, said arcuate wall being complementary to and received in said arcuate opening for maintaining said base and lid members in a predetermined relative position, said base and lid members defining therebetween an enclosed insulated chamber, in which said switch is mounted, said base and lid members having cooperating elongated extensions defining an insulated conduit for said electrical cable and extending respectively from said arcuate opening and said arcuate wall to the free ends thereof, said free ends being located in adjacent spaced relation in an opening in said lamp shade to clamp said cable therebetween, and means maintaining said switch enclosure in said lamp shade.

12. The device as defined in claim 1 1 wherein one of said extensions is substantially fiat and the other of said extensions is generally U-shaped in crosssection, said flat extension engaging the free edges of said U-shaped extension to form said insulating conduit therebetween.

13. A device as defined in claim 12 wherein said extensions each includes cooperating secondary members extending substantially at right angles to said extensions and being located in said opening in the lamp shade, said secondary members forming the free ends of said elongated extensions and having closely adjacent spaced edges clamping said cable therebetween.

14. A device as defined in claim 13 wherein said closely adjacent spaced edges are serrated.

15. A device as defined in claim 13 including means maintaining said base and lid members in mating relation.

16. A device as defined in claim 15 wherein said lastmentioned means comprises an aperture in one of said lid and base members and an elongated tongue member extending from the other of said lid and base members and having an enlarged free end snap fit in said aperture.

17. A device as defined in claim 16 wherein said means mounting said switch enclosure in said lamp shade comprises a bracket secured at one end to the interior of said lamp shade and at its other end to said base member.

Claims

1. A device for insulating a switch in a lamp and for insulating and locking an electrical cable passing through the lamp''s shade to the switch, said device comprising an enclosure formed of an electrical insulating material and defining an enclosed insulated chamber in which said switch is mounted, said enclosure having an elongated extension forming an insulated conduit for the electrical cable passing through the lamp''s shade to the switch in said chamber, said extension having a free end portion located in an opening in said lamp shade and said free end portion having at least two closely adjacent spaced edges clamping said electrical cable in a relatively fixed position therebetween.

6. A device as defined in claim 5 wherein said elongated arms are respectively located in mating relation adjacent said opening in said peripheral wall and adjacent said arcuate wall, with one of said arms being generally flat and the other of said arms being generally U-shaped in cross-section, said flat arm engaging the free edge of said U-shaped arm to form said insulated conduit therebetween.

10. A device as defined in claim 9 wherein said last-mentioned means comprises an aperture in one of said lid and base portion and an elongated tongue member extending from the other of said lid and base portion and having an enlarged free end snap fit in said aperture.

11. A device for insulating a switch in a lamp and for insulating and locking an electrical cable passing through the lamp''s shade to the switch, said device including means defining a switch enclosure, said means being formed of an electrical insulating material and comprising a generally annular base member having a peripheral wall extending upwardly therefrom, said wall having a free edge and an arcuate opening therein; a generally circular lid member engaging said free edge about its periphery and having one arcuate wall portion extending therefrom, said arcuate wall being complementary to and received in said arcuate opening for maintaining said base and lid members in a predetermined relative position, said base and lid members defining therebetween an enclosed insulated chamber, in which said switch is mounted, said base and lid members having cooperating elongated extensions defining an insulated conduit for said electrical cable and extending respectively from said arcuate opening and said arcuate wall to the free ends thereof, said free ends being located in adjacent spaced relation in an opening in said lamp shade to clamp said cable therebetween, and means maintaining said switch enclosure in said lamp shade.

12. The device as defined in claim 11 wherein one of said extensions is substantially flat and the other of said extensions is generally U-shaped in cross-section, said flat extension engaging the free edges of said U-shaped extension to form said insulating conduit therebetween.

16. A device as defined in claim 15 wherein said last-mentioned means comprises an aperture in one of said lid and base members and an elongated tongue member extending from the other of said lid and base members and having an enlarged free end snap fit in said aperture.