US2977563A - Wiring device - Google Patents

Description

March 28, 1961 s. c. LENNOX WIRING DEVICE Filed April 26, 1956 33 INVENTOR Geo rge C. Lennox WITNESSES ATTORNEY wrnnso onvrcn George C. Lenuox, Southbury, Conn., assignor to The Bryant Electric Company, Bridgeport, Conn., a corporation of Connecticut Filed Apr. 26, 1956, Ser. No. 580,806

Claims. (Cl. 339-31) My invention relates to electric wiring devices, and more particularly to lampholders for fluorescent lamps.

As is well known, the design of fluorescent lamps has been standardized to provide a pair of spaced bases, each of which is provided with one or more outwardly extending contact pins for providing means whereby the lamp may be electrically energized. Suchoutwardly extending contact pins have been unsatisfactory due to their fragility whereby many have been broken oft in the field, and alsodue to the fact that under certain circumstances they constitute an electrical hazard. Accordingly, a new type of lamp base has been designed which has an outwardly extending portion with a hollow chamber formed therein in which a pair of spaced contacts are located. Although this construction overcomes the above-mentioned disadvantage of outwardly extending contacts, it has necessitated that a new type of lampholder be provided in which the new type of lamp may be supported.

Heretofore various types of lampholders have been pro vided for such new lamps but they have not been entirely satisfactory, as they have employed components which are relatively expensive to assemble. Also, some of such lampholders have been unsatisfactory in that a good electrical contact has not been established between the recessed contacts of the lamp and the contacts of the lampholder.

As is also well known, in supporting elongated fluorescent lamps, it is customary to provide alampholder having a retractable plunger which is cooperable with a fixed lampholder so-that the lamp may be resiliently located between the lampholders. Lampholders designed to accommodate the new type of lamp have provided separate lamph-olders for the fixed end and the retractable plunger end, which separate lampholders have added to the expense of each of the lampholders.

A particular problem which has also been'met when employing a retractable plunger lampholder is the releasing of the retractable plunger from its depressed position so that the plunger rapidly engages the face of the lampnections are to be made.

Another object of my invention is to provide a new and improved lampholder of a construction so that a separate plunger may be reciprocably or fixedly secured to the housing of the lampholder.

A further object of my invention is to provide a new and improved lampholder having a housing with an opening in one of its faces for receiving a plunger therein and which housing and plunger have cooperable means for permitting the plunger to be located in either a fixed or movable position with respect to the housing.

A more specific object of my-invention is to provide a new and improved lampholder having a cup-shaped hous- United States Patent Patented Mar. 28, 1961 2 ing withan opening in the housing for receiving a plunger therein, a guide located on the inner surface of each side of the housing for slidably receiving outwardly extending projections on the plunger and which plunger is rotatable so thatthe projections cannot be received within the guides.

Still another object of my invention is to provide a new and improved lampholder having a plunger retractable therein, which plunger has extending means formed integral therewith for maintaining the point of impact between the housing and the plunger as close as possible to the body of the plunger.

A more specific object of my invention is to provide a new and improved lampholder having a plunger retractable therein which is provided with a trapezoidal shaped bevel engageable with the housing of the lampholder to maintain the point of impact between the housing and the plunger as close as possible to the body of the plunger.

A further object of my invention is to provide a new and improved lampholder having a one-piece extending contact which is provided with a lancing to pivotally support the contact in the lampholder.

Another object of my invention is to'provide a new and improved two-piece elongated lampholder, which parts are secured together by means located on the central axis of the lampholder.

A more specific object of my invention is to provide a new and improved lampholder having a retractable plunger with a pivotally mounted contact therein, and a spring means for biasing the contact into engagement with the plunger and the plunger outwardly from the lampholder housing.

These and other objects of my invention will become more apparent upon consideration of the following detailed description of a preferred embodiment thereof,

when taken in conjunction with the attached drawings, in which:

Figure l is a front elevational view of a wiring device constructed in accordance with the principles of my invention;

Fig. 2 is across-sectional view of the wiring device shown in Fig. 1 taken substantially along the lines IIIl thereof, and with portions thereof being shown in elevation;

Fig. 3 is a back elevational view of the housing of the device shown in Fig. 1 with the cover removed;

Fig. 4 is an elevational view of the inner side of the back cover of the device as shown in Fig. 1;

Fig. 5 is an inner end view of the plunger utilized in the device as shown in Fig. l; v

Fig. 6 is a cross-sectional view of the plunger as shown in Fig. 5 taken substantially along the lines VI-VI Referring to the drawings, it will be noted that one form of lampholder constructed in accordance with the principles of my invention comprises a hollow insulating housing 2 having an open back which is adapted to be covered by means of an insulating back cover 12 so as to form a unitary lampholder structure. As shown, an insulating plunger 4 is also located within housing 2. As will become apparent herein, housing 2, plunger- 4 and cover 12 are formed so that all the component parts of the lampholder may readily be located in their proper position and captively held thereby when the cover 12 is secured to the housing 2. Although housing 2, plunger 4 and cover 12 may be formed from any suitable insulating material, each is preferably formed from a molded insulating material which may readily be provided with the requisite structure as hereinafter described.

As shown, housing 2 has its lower or base end enlarged laterally outwardly from the sides of the housing so that its base 14 is open at one end and on the bottom. The upper portion of housing 2 is provided with a curved top 16. As shown in Figs. and 6, the plunger 4 is cylindrical in form and has a pair of opposed outwardly extending tabs 18 at one of its ends which is located inwardly of the sides of housing 2. In order that plunger 4 may extend outwardly from the housing 2, the front wall of housing 2 is provided with a circular opening 24 adjacent to and substantially concentric with the curved top 16 for closely receiving the cylindrical portion of plunger 4 therein. In order that plunger 4 may be supported within the curved top 16 of housing 2, the inner surface of the side walls of housing 2 is provided with a pair of opposed slots 22 which extend inwardly from the open back toward the front wall of housing 2, and which are of a size to closely receive the tabs 18 on plunger 4 therein. It will be noted that slots 22 terminate short of the front wall of housing 2 to form diametrically opp sed flanges 26 inwardly adjacent the front wall of housing 2 so that the outward travel of plunger 4 through opening 24 is limited by the engagement of tabs 18 with the flanges 26. To additionally slidably support plunger 4 within the curved top 16, housing 2 is provided with stop projections 28 which extend inwardly from the inner surfaces of the sides of housing 2 and which are each provided with a curved inner portion engageable with a portion of the curved undersurface of the plunger 4.

As has been indicated, cover 12 is formed so as to enclose the open back of housing 2 and when in this assembled position, the plunger 4 is biased outwardly through opening 24 by means of a pair of laterally spaced, closed end, helical springs (only one of which is shown) which extend from the inner surface of cover 12 into elongated diametrically spaced cylindrical recesses 30 which extend axially inwardly of plunger 4 from its inner end. Springs 3 may be formed from any suitable resilient material, such as steel spring wire, and are provided with a closed height which is less than the space allowed for springs 8 when the plunger 4 is in its fully depressed position. As more clearly shown in Figs. 5 and 6, a recess 30 is located adjacent each tab 18 with their diameters being coincident with a diameter of the plunger 4.

In order that electrical connections may readily be made to the lampholder, a pair of laterally spaced elongated contact strips 32 (only one of which is shown in Fig. 7) are provided which extend from the inner ends of springs 8, respectively, along the inner surface of cover 12 to the open bottom of the assembled lampholder. As can readily be appreciated, the inner surface of cover 12 is provided with laterally spaced formed slots 34 for closely receiving contact strips 32 therein so that the contact strips 32 are supported by the cover 12 and so that the contact strips 32 are adequately electrically insulated from each other. In particular, an outwardly extending barrier 36 is provided integral with cover 12 which extends centrally between the slots 34 in order that the housing 2 and cover 12 may be secured together in a novel manner as hereinafter described.

As shown, the lower ends 33 of contact strips 32 are bent at approximately right angles to the portion extending along the inner surface of cover 12 so as to provide an area to which wiring connections may be made in any suitable manner, such as by means of binding screws 38 threadedly engaging the lower ends 33 of the contact strips 32. Inasmuch as contacts 32 are utilized for electrical purposes, they are formed from any suitable electrical conducting material, such as an alloy of copper, which may readily be formed as described herein. It will also be noted that the open bottom of the assembled lampholder may, if desired, be enclosed by means of an insulating plate 37 which is secured so as to extend below the binding screws 38, in any suitable manner. The upper end of each contact strip 32 is provided with an integral inwardly extending circular projection 39 which is of a diameter to be closely received within the inside diameter of the spring 8 so that the end of the spring 8 cooperable therewith is restrained from sliding over the inwardly facing surface of the contact strip 32.

Referring to Figs. 1, 2, 6 and 7, it will be noted that the plunger 4 is provided with an elongated oval recess 40 which extends inwardly from the outer end of plunger 4. In order that recess 40 may be cooperable with the recesses 30, the elongated axis of recess 40 is coincident with the diameter of the plunger 4 upon which the recesses 30 are located and has its inner end spaced from the inner ends of recesses 30 to form an integral ban'ier 42 therebetween. An integral projection 44 is also provided on plunger 4 which extends outwardly from the barrier 42 centrally into recess 40 and which is in alignment with the portion of plunger 4 located between the recesses 30. Recess 40 is also connected to each recess 30 by means of a slot 46 extending through the barrier 42, which slots 46 are located on the diameter of plunger 4 upon which the elongated axis of recess 40 and the diameters of recesses 30 are located. Slots 46 are spaced diametrically from each other a distance somewhat less than the width of projection 44 and, accordingly, projection 44 is provided with inwardly extending slots 48 along each of its sides in alignment with the adjacent ends of slots 46. Each pair of slots 46 and 48 are provided to receive novel shaped electrical contacts 50 shown in Fig. 8 which are formed from any suitable electrical conducting material such as an alloy of copper, and which may be treated in any suitable manner, such as silver plating,'so as to have better are resistant characteristics.

As has been indicated, a new type of lamp base has been designed which has outwardly extending lamp contacts located in a recessed chamber. The recess 40 of the lampholder of my construction is of a size to closely receive the base of such a lamp with the projection 44 being located between the lamp contacts in the base of the lamp. Accordingly, contacts 50 function to make electrical contact with the lamp contacts; however, with the contact 50 of my construction, such contact is obtained in an entirely new and novel manner. As shown in Fig. 8, contact 50 is elongated and is provided with a lower tip 52 which is of a width so as to be closely received within the internal diameter of spring 8. Contact 50 is also provided with an integral outwardly extending shoulder 54 at one of its sides which extends laterally outwardly at the upper end of the lower tip 52 so that the end coil of the spring 8 engages the shoulder 54 when the lower tip 52 is inserted within the spring 8. It will also be noted that one side of contact 50 is provided with an integral outwardly extending lance or struck-out portion 56 which has an upper knife edge 55 located above the shoulder 54.

The upper end of contact 50 is provided with a small outwardly extending tip 58 which is of a lateral width somewhat greater than the width of shoulder 54, and which is located above the shoulder 54 but offset inwardly toward the central longitudinal axis of contact 50. will particularly be noted that the side 60 extending from the outer end of shoulder 54 toward tip 58 is sloped towards the central longitudinal axis of contact 50 so as to form one side of the tip 58. The side of contact 50 opposite side 60 is also of novel form and comprises a laterally outwardly extending projection 62 which extends longitudinally from approximately the upper end of the lance 56 to a point spaced below the outer end of tip 58. Of particular importance is the fact that the outer edge 64 of projection 62 is provided with a curvature which has a chord extending generally towards the central longitudinal axis of contact 50 as it extends towards the upper end of contact 50.

In assembling the lampholder, contacts 50 are initially inserted into the inner ends of each of the recesses 30 so that the tip 58 extends through the slot 46 as more particularly shown in Fig. 8. It Will be noted that the movement of each contact-50 outwardly through slot 46 is limited by the engagement of the upper knife edge 55 on the lance 56 with the inner side of barrier 42 adjacent the slots 46. In order to facilitate such insertion of contacts 50, the bottom of each recess 30 is provided with an outwardly inclined surface 20 on each side of its slot 46 adjacent the portion of plunger 4 between the recesses '30. By providing inclined surfaces 20, contacts 50 are very easily located in place if they are not precisely aligned with slots 46 when first dropped into recesses 30, by merely jiggling the plunger 4 which causes the tip 58 to be guided by and slide down inclined surfaces 20 so that the entire contact 50 is then aligned with and drops into the slots 46. Such a rapid locating of the contacts 50 within the slots 46 is particularly desirable in mass production and for such purposes a vibrating mechanism for vibrating the plungers 4 with the contacts 50 therein may be provided. Thereafter, when plunger 4, springs ti and cover 12 are assembled as indicated,-the springs 8 bias the contacts 50 outwardly through slots 46.

In particular, however, it will be noted (Fig. 8) that, as the knife edge 55 of each lance 56 is located between the outer ends of its cooperable slot 46,.and the shoulder 54 of each contact 51} is located between the knife edge 55 and the portion of plunger 4 between recesses 30, each contact 50 will be pivotally supported so that the upper tip 58 is normally biased about edge 55 so that the outer side of tip 58 is moved laterally out of its cooperable slot 48 (see Fig. 8) and the side 60 adjacent shoulder 54 engages slot 48 or projection 62 engages the outer end of slot 46 to limit pivotal movement of contact 50. With such construction, when the contact tips 58 are engaged by the contacts in the lamp base, each contact tip 58 is resiliently supported so as to be pivotally movable about the knife edge 55 inwardly toward each other.

Another feature of my invention is in the location of the means to secure the housing 2 and cover 12 together. As shown, housing 2 is provided with vertically spaced projections 68 and 70 which extend inwardly centrally between the sides of housing 2, and the inner ends of which engage the inner end of the barrier 36 on cover 12. Projection 68 and barrier 36 are located so that their upper ends are below the opening 24, whereby the lower surface of plunger 4 may be supported throughout its travel by the upper ends of projection 68 and barrier 36. Projection 70 is located between the sides of housing 2 and may have its sides formed to support the edges of the lower ends 33 of contact strips 32. Although various securing means may be utilized, as shown, clearance openings 72 and 74 are provided in projections 68 and 7 0, respectively, which are aligned with threaded openings 76 and 78, respectively, in barrier 36 so that standard screws 77 may be used to secure cover 12 to housing 2 in a well known manner. In particular, however, it will be noted that the front of base 14 is provided in the standard manner with a cross shaped slot 75 which extends inwardly of base 14 from its outer edge centrally of the housing 2. Slot 75 is customarily used for the purposes of supporting the lampholder. Accordingly, in order that slot 75 may be utilized in its customary manner, opening 74 has its outer end at the bottom of slot 75.

In order to prevent damage due to rapid release of the plunger 4, as previously indicated, the outwardly facing B sides of tabs 18 on plunger 4 have each been provided with a fillet 80 (Fig. 6) which extends from the outer edge of tabs 18 to the outer surface of plunger 4 adjacent thereto. Fillets 80 are engageable with the free edges of the flanges 26 on housing 2. Inasmuch as fillets 80 are angularly disposed with relation to the outer surface of plunger 4, the force of impact therebetween is directed angularly downwardly through the fillets 80 so that the larger section of plunger 4 absorbs the greater component of shock loading rather than the smaller cross section of the tabs 18. Although fillets 80 may be of various cross sections, as shown, a cross section having a fiat angularly extending outer surface, such as trapezoidal, is desired in order to better direct the shock force to the plunger 4.

Although as heretofore described, plunger 4 is reciprocably located within housing 2, it may also be located within housing 2 so as to be stationary, as shown in Fig. 7. Referring. also to Figs. 5 and 6, it will be noted that each tab 18 extends further laterally in one direction from the diameter of the plunger 4 upon which slots 46 are located than in the opposite direction so that the tabs 18 are not symmetrical with respect to the diameter of plunger 4 passing through the centers of recesses 34] and the centers of slots 46. Similarly, in Fig. 3, slots 22 are not symmetrically disposed with relation to the horizontal diameter of opening 24, but extend laterally toward the top 16 a greater distance than they extend toward base 14 with reference to the diameter of opening 24 extending horizontally with respect to Fig. 3. Slots 22 are formed, as has been indicated, so that if the plunger 4 located as shown in Fig. 5 were inserted in housing 2, as shown in Fig. 3, tabs 18 would be closely and slidably receivedvin the slots 22 and the plunger 4 would pass out- 'wardly through the opening 24. However, by rotating plunger 4, 180, the longer portion of tabs 18 would no longer coincide with the longer portion of slots 22, but would be located so that the outer end of the longer portion of tabs 18 would extend over the shorter portion of slots 22. Accordingly, such engagement of tabs 18 would prevent the plunger 4 from being moved outwardly through opening 24. In order that the face of plunger 4 may then be located so as to be substantially flush with the face of housing 2, the stop projections 28 on housing 2 are offset inwardly of housing 2 so that the edge of tab 18 engageable therewith is located inwardly of housing 2. Further, in order to provide sufiicient clearance for the inner edge of tabs 18, the inner surface of cover 12 is provided with opposed recessed portions 81 in which the inner end of tabs 18 are located when plunger 4 is in its depressed position. As shown, recessed portions 81 are longer than tabs 18 to permit some rotational movement of 4 plunger 4 in its depressed position, which rotational movement is limited by the engagement of the sides of tab 18 with the ends of recessed portions 81. Of course, in this embodiment, the cover 12 would have to be removed to provide for changing the position of the plunger'4.

Thus, it will be noted that I have provided a lampholder for the new type of lamp base which has several novel cooperable features. Of great importance is the pivot support and biasing of the contacts so that they are biased diametrically away from each other.

By spacing the lampholder contacts properly, the spaced contacts of the lamp force the lampholder contacts toward each other where a good electrical contact is assured at all times between such contacts. By further nesting the larnpholder contacts in the springs, the lam-pholder contacts are also biased outwardly of housing 2 to insure that such electrical contact is maintained at all times. As can also readily be appreciated, the ability to obtain both a fixed and retractable plunger lampholder by using the sameparts results in a substantial saving to both the manufacturer and supplier. Further, the use of fillets to direct the shock loading with a retractable plunger substantially reduces damage to the housing or plunger of the lampholder in the field.

Having described a preferred embodiment of my invention in accordance with the patent statute, it is desired that the invention be not limited to the specific construction shown and described, rather that it be limited only by the spirit of its broad principles.

I claim as my invention:

1. A wiring device comprising a hollow housing having an opening therein, a plunger slidably mounted in said housing opening, mutually engageable means on said housing and said plunger for limiting outward movement of said plunger through said opening, at least one slot extending through said plunger, a generally planar, elongated contact being positioned to extend through said slot for engagement with a load terminal, said contact having an integral struck-out portion extending laterally from one side thereof and engaging an inner surface of said plunger for limiting outward movement of said contact through said slot, a portion of said contact forming an abutment that is laterally offset from said struck-out portion, and resilient means being mounted in said housing for biasing said contact outwardly of said slot and said plunger outwardly of said opening, said resilient means engaging said contact abutment normally to bias said contact pivotally about said struck-out portion to one side of said slot and toward said load terminal.

2. A wiring device comprising a hollow housing, means forming a part of said housing for supporting at least one contact, at least one elonagted slot extending through said supporting means from one side thereof, a generally planar, elongated contact extending through said slot for engagement with a load terminal and having an integral struck-out portion extending laterally from one side thereof and engaging an inner surface of said supporting means for limiting outward movement of said contact through said slot, a portion of said contact forming an abutment that is laterally offset from said struck-out portion, and resilient means being mounted in said housing for biasing said contact outwardly of said slot, said resilient means engaging said contact abutment normally to bias said contact pivotally about said struck-out portion to one side of said slot and toward said load terminal.

3. A wiring device selectably providing fixed or resilient support for a load device, said wiring device comprising a hollow housing having an opening in one wall thereof, a plunger being provided for support relative to said housing, said' plunger and said housing having guide and abutment means, said plunger having one position relative to said housing in which said guide means cooperate to provide sliding movement of said plunger relative to said housing and in which said abutment means cooperate to limit movement of said plunger outwardly of said housing, contact means being supported by said plunger, resilient means mounted in said housing and biasing said plunger and said contact means outwardly of said opening, said plunger having another position relative to said housing in which said guide means are offset from each other and in which said abutment means cooperate to retain'said plunger in a fixed relation with said housing.

4. A wiring device selectably providing fixed or resilient support for a load device, said wiring device comprising a hollow housing having an opening in one wall thereof, spaced, elongated slots in the opposed surfaces of spaced sides'of the hollow of said housing, respectively, which extend outwardly of said hollow but terminate short of said opening to provide respective abutments, a plunger having opposed outwardly extending ribs for cooperative engagement with said slots to support slidably said plunger in one position relative to said housing, said abutments limiting the outward movement of said plunger in said one position, contact means being supported by said plunger, resilient means mounted in said housing and biasing said contact means and said plunger outwardly of said opening, said slots and said ribs being laterally offset from a reference centerline of a lateral section of said hollow of said housing, respectively, so that said ribs and said slots are displaced from said cooperative engagement when said plunger is removed through substantially from said one position to another position in which said plunger is fixed relative to said housing, and abutment means for retaining said plunger in said another position.

5. A wiring device selectably providing fixed or resilient support for a load device, said wiring device comprising a hollow housing having an opening in one wall thereof, spaced, elongated slots in the opposed surfaces of spaced sides of the hollow of said housing, respectively, which extend outwardly of said hollow but terminate short of said opening to provide respective abutments, a plunger having opposed outwardly extending ribs for cooperative engagement with said slots to support slidably said plunger in one position relative to said housing, said abutments limiting the outward movement of said plunger in said one position, contact means being supported by said plunger, resilient means mounted in said housing and biasing saidcontact means and said plunger outwardly of said opening, said slots and said ribs being laterally offset from a reference centerline of a lateral section of said hollow of saidhousing, respectively, so that said ribs and said slots are displaced from said cooperative engagement when said plunger is removed through substantially 180 from said one position to another position in which said plunger is fixed relative to said housing, and abutment means for retaining said plunger in said another position, said housing including a cover secured thereto and closing said cavity oppositely of said one wall, said abutment means being provided at least in part on said cover.

References Cited in the file of this patent UNITED STATES PATENTS 2,310,142 Woodman Feb. 2, 1943 2,464,643 Kulka Mar. 15, 1949 2,511,037 Bedoiseau June 13, 1950 2,716,738 Pistey Aug. 30, 1955 2,716,739 Lemmers Aug. 30, 1955

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