Lampholders for electric discharge lamps

Nov. 7, 1967 j.m. pistey 3,351,884

LAMPHOLDERS FOR ELECTRIC DISCHARGE LAMPS

Original Filed Oct. 1, 1963 ₂ Sheets-Sheet 1

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J. M. PISTEY

Nov. 7, 1967

LAMPHOLDERS FOR ELECTRIC DISCHARGE

Original Filed Oct. i, 1963

3,351,884

LAMPS

Sheets-Sheet 2

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United States Patent Office

3,351,884 LAMPHOLDERS FOR ELECTRIC DISCHARGE LAMPS John M. Pistey, Fairfield, Conn., assignor to General Electric Company, a corporation of New York Original application Oct. 1, 1963, Ser. No. 313,061, now Patent No. 3,290,638, dated Dec. 6, 1966. Divided and this application Sept. 22,1965, Ser. No. 489,306 2 Claims. (Cl. 339—52)

ABSTRACT OF THE DISCLOSURE

A split-housing lampholder with two housing sections. One housing section has a pair of projections which extend into the other housing section and engage an edge of two edgewise mounted contact strips in order to firmly hold the contact strips in the other housing section. Each contact strip has an angulated pressure lock portion, and one of the projections provides a wall for two conductor receiving apertures in the other housing section adjacent to the pressure lock portions.

3,351,88^

Patented Nov. 7, 196’ by a contact means, such as a washer, which engages on end of the plunger spring. The plunger spring serves a a current carrying member of the electrical circuit, an&lt; the other end of the spring is in electrical contact with : contact strip to which the leads from the ballast are con nected. Once the lamp is in the lampholders, sufficien axial force must be exerted by the plunger spring t&lt; establish a good electrical contact between the lamp pii ana contact strip. Also, the plunger should have suf ficient travel to reliably handle lamps within the rang&lt; of tolerances for the lamp and for mounting the lamp holders. The manufacturing tolerance for a typical fluo rescent lamp are plus or minus Vs of an inch and th&lt; mounting tolerances of the lampholders are plus or minus Ae of. an inch. In view of the lamp and lampholdei mounting tolerances it is particularly desirable that the plunger be allowed to retract into the housing as far'a* possible.

A general object of this invention is to provide an improved lampholder for electric discharge lamps such as fluorescent lamps.

Another object of the invention is to provide an improved lampholder utilizing molded parts of relatively shallow depth.

A further object of the present invention is to provide an improved lampholder construction using parts that can be more efficiently molded.

In accordance with one form of the invention, I have provided an improved lampholder for a fluorescent lamp with a split insulating housing arrangement. The insulating housing, arrangement includes a first and a second housing section which provide a front and a rear vertical wall and which are joined to form side walls disposed in perpendicular relationship to the vertical walls. One of the housing sections is formed with a projection that extends into the other housing section to provide a guide wall for the conductor receiving aperture formed in the other housing section. The projection also engages a ₍ resilient, contact strip disposed in edgewise relation along the vertical wall of the other housing section to hold the strip therein. At one end the resilient contact strip is formed with an angulated pressure lock portion that is disposed at the inner side of the conductor receiving aperture for engaging a conductor in locking relation. At the other end the resilient contact strip includes a portion for connection in electrical circuit with the fluorescent lamp.

With the split housing arrangement it was possible to reduce the cost of the molded parts and to simplify the assembly of the other components in the molded parts because of the relatively shallow depth and configuration of the molded parts. Further, for a given axial width of a high voltage lampholder, it was possible to provide an increase in the travel of the lampholder plunger.

Further aspects of my invention will become apparent upon, consideration of the following more detailed description. The subject matter which I regard as my invention is set forth in the appended claims. The invention, thereof may be best understood by referring to the following description taken in conjunction with the accompanying drawings in which:

FIGURE 1 is a side eleyational view showing a general arrangement of a fluorescent lamp supported between a pair of lampholders embodying one form of the invention;

FIGURE 2 is an enlarged front elevational view of the high voltage lampholder shown at the right end of the lamp in FIGURE 1 with the plunger in the extended

This application is a division of my co-pending application Ser. No. 313,061, filed Oct. 1, 1963, and now Patent No. 3,290,638.

This invention relates generally to lampholders for electric discharge lamps and more particularly to such improved lampholders for use in conjunction with fluorescent lamps.

A fluorescent lamp of the single pin type is generally supported at one end by a lampholder having a retractable spring-biased plunger (high voltage lampholder) and at the other end by a lampholdrer that provides a fixed support. Thus, the fluorescent lamp is resiliently held between the pair of lampholders. The lampholders also provide the means through which connections are made from the ballast to the lamp. To place the fluorescent lamp in the lampholders, the pin at one end of the lamp is first inserted in the lampholder with the springbiased plunger, and the spring-biased plunger is compressed until the pin at the other end of the lamp can be engaged in the other lampholder.

. In. a commonly used lampholder construction the lamp pin is inserted into an aperture formed in the· plunger and an axial pressure against the plunger causes the plunger to be retracted into the housing. The housing of such a lampholder is usually constructed of one molded base formed with a relatively deep cavity in which the plunger, spring and other parts are assembled. After the parts are assembled a cover which closes the cavity is attached.

A disadvantage of such a conventional arrangement is that because of the depth of the base the cure time required for the molded part is relatively longer than would be the case if the part molded were of shorter depth. Thus, to enhance the efficiency of the molding operation it is particularly desirable in the manufacture molded part, it will be appreciated that it is possible to thereby reduce the cost of the molding operation since more cavities may be used per mold and shorter curing times may be employed. Another disadvantage in using a _Q5single molded housing construction with a relatively deep cavity is that the assembly procedures are complicated for assembling the parts in the deep cavity. It will be apparent that it is generally easier to assemble parts in a relatively shallow cavity.

The. electrical contact with the pin of the fluorescent - _______„___________ lamp in the high voltage lampholder is usually provided position (lamp disengaged);

3,351,884 are preferably formed from any moldable electrically insulating material such as urea.

As is best seen in the exploded view of FIGURE 4, the plunger 17 is cylindrical in shape and includes a flange 23 which engages an annular stop shoulder 24 formed in the front housing section 18 when it is in the extended position. Also the plunger 17 includes a pair of opposed grooves or slots 25, 26 which engage the opposed axially extending ribs 27, 28 formed in the plunger-receiving opening 21. When the plunger 17 is in the outwardly extended position as shown in FIGURE 3, it will be seert that the flange 23 is in contact with the annular stop shoulder 24 formed in the front housing section 18 and any further outward axial movement of the plunger 17 is thereby restrained. The plunger 17 is formed with a piiireceiving aperture 30 and a relatively larger opening 31 for receiving a current carrying spring 32.

The spring 32, as shown in FIGURE 3, is centered at one end by a centering means which is comprised of a ribbed boss 33 formed on the vertical wall 34 of the rear housing section 19. At the other end the spring. 32 engages a contact washer 35 which provides an electrical connection between the lamp pin and the spring 32. The spring 32 may be formed from any suitable resilient and 25 electrically conductive material, and in the fully extended position is designed to exert a spring force to maintain the plunger 17 in the extended position.

As is best seen in FIGURE 5, the front housing section 18 is formed with a foot or projection 37 which 30 extends outwardly of the front housing section 18. The projection 37 includes three rib portions 38, 39 and 40 and engages the rear housing section 19 in interlocking relation to provide structural rigidity between the housing sections 18 and 19. It was found that with the pro35 jection 37 extending into the rear housing section 19, as shown in FIGURES 3 and 8, the split housing arrangement had the requisite mechanical strength and. permitted the use of molded housing sections 18, 19 having a relatively shallow depth. This results in the important adyan4.0 tage that more cavities per mold and shorter cure times are possible, as compared to a lampholder arrangement utilizing a non-split housing arrangement. Also, the projection 37 provides for an accurate fit between the two housing sections 18 and 19.

Referring to FIGURES 5 and 8, the end surface of the rib portion 38 provides a guide wall 41 for the conduction receiving aperture 42 and serves to guide a conductor or lead into proper pressure lock engagement. The end surface of portion 39 locks the contact strip 45 in the rear 50 housing section 19 and also provides a wall 43 for the tool-receiving aperture 44.

As is seen in FIGURES 6 and 7, the resilient contact strip 45 includes an angulated pressure lock portion .46 and spring contact portion 47. The pressure lock portion ..... ... ”· &gt; that the contact strip 45 can be held in position within the rear housing section 19 during assembly. Further, it will be seen that the pressure lock portion 46 is disposed so that the end is located at the inner side of the conductor is formed with an indentation 49 for facilitating the entry of the conductor into pressure lock engagement.

The spring contact portion 47 of the contact strip 45 includes tapered ear 50 which, as shown in FIGURE 6, 33, and also includes a transversely extending contact portion 51 which extends in a direction parallel to the vertical wall 34 of the rear housing section 19. The contact strip 45 may be formed from any suitable electrical con3

FIGURE 3 is a sectional view taken generally along he line 3—3 of FIGURE 2;

FIGURE 4 is a view in perspective of the plunger and i fragmentary portion of a housing section of the lamprolder illustrated in FIGURES 2 and 3 illustrating the «operative relationship between the housing section and he plunger;

FIGURE 5 is a rear elevational view of the front hou.sng section of the high voltage lampholder shown in -IGURE 1;

FIGURE 6 is an enlarged front elevational view of the rear housing section of the high voltage lampholder shown in FIGURE 1 with the spring positioned on the lentering means;

FIGURE 7 is an enlarged perspective view of the con:act strip shown in FIGURE 6;

FIGURE 8 is a top view of the high voltage lamphold;r shown in FIGURE 1;

FIGURE 9 is a front elevational view of the low voltage lampholder shown at the left end of the arrangement shown in FIGURE 1;

FIGURE 10 is an enlarged sectional view taken generally along the line 10—10 of FIGURE 9;

FIGURE 11 is an enlarged front elevational view of the rear housing section of the low voltage lampholder shown in FIGURE 9;

FIGURE 12 is an enlarged rear view of the front housing section of the lampholder shown in FIGURE 9 with the front housing section removed; and

FIGURE 13 is an enlarged view of the contact strip shown in FIGURE 12.

Having more specific reference now to FIGURE 1 of the drawings, I have illustrated therein a fluorescent lamp 10 of the single pin type supported at the right end by a high voltage lampholder 11 and at the left end by a low voltage lampholder 12. The lampholders 11, 12 in which the invention is embodied, are supported from a plate 13. The plate 13 may form the part of a lighting fixture or other surface on which it is desired to attach the lampholders 11, 12. The fluorescent lamp 10 which is supported by lampholders 11 and 12 includes a tubular glass envelope 14 with a pair of bases 15 and 16, each of which have a single pin (not shown) extending therefrom.

It will be apparent from the general arrangement shown 45 in FIGURE 1 that for a given lamp length the lampholders 11 and 12 must be mounted and attached to the supporting plate 13 in a predetermined spaced relation. With the lampholders 11, 12 so mounted the lamp 10 is inserted into the lampholders by first depressing a springbiased plunger 17 into the lampholder 11 sufficiently so that the pin at the left end of the lamp 10 can be inserted in the aperture provided in lampholder 12. To insert the lamp 10, it is held at an angle to the center line joining --------------_x. . . the two lampholders 11, 12 and is forced towards the 55 46 is disposed in the cavity 49 with an interference fit so lampholder 11 to push the plunger 17 inwardly. When the ..... ‘ ^: * pin at the left end of the lamp 10 is engaged in lampholder 12, the lamp 10 is resiliently supported between the two lampholders 11 and 12. --------- — - ,,. , , ,.

Having more particular reference now to the FIGURES go receiving aperture 42. The end of pressure lock portion 2 to 7,1 will now more particularly describe the construction of the high voltage lampholder 11, which is shown at the right end of the lamp mounting arrangement illustrated in FIGURE 1. It will be noted that a split housing arrange- ..... ... . .

ment is provided and is comprised of two molded hous- 55 serves to position and lock the spring 32 against the boss ing sections 18 and 19. For convenient reference, the sec- ’ ---^Λ·-^Δ— - * tion 18 which is adjacent to the lamp 10 will hereinafter be referred to as the front housing section and the section 19 joined therewith shall be referred to as the rear --.-. - , .

section. The front and rear housing sections 18, 19 are 70 ducting material, preferably phosphor bronze, which may joined to form a unitary housing structure by a suitable securing means such as an eyelet or rivet 20. The plunger 17 is slidably mounted within plunger-receiving openings 21, 22 in the front and rear housing sections 18, 19. The .

front and rear housing sections 18, 19 and the plunger 75 52 formed on the wall 34 and the end of the spring 32 be readily formed to the configuration described herein. It will be noted that the contact strip 45 is disposed in edgewise relation with respect to the wall 34 and that the transverse contact portion 34 is situated between a pad §,351,§84 5 whereby the spring 32 always presses against the transverse contact portion 51 irrespective of the position of the plunger 17.

When the spring 32 is inserted over the centering means or element 33 on the wall 34, the spring 32 effects a slight outward displacement of the spring contact portion 47. The ear 50 is held resiliently against the spring 32. This provides the advantage that a spring type of engagement is provided between the ear 50 and the spring 32 which permits the spring 32 to be held in position during assembly.

In assembling the high voltage lampholder 11, the contact strip 45 is initially placed in the cavity 9 of the rear housing section 19 and the spring 32 is clipped in position between the centering element 33 and the tapered ear 50, as shown in FIGURE 6. The plunger 17 is assembled in the plunger receiving opening 21 of the front housing section 18, and the contact washer 35, which provide the electrical contact with the lamp, is inserted into the spring receiving opening 31 of the plunger 17. The front and rear housing sections 18, 19 are then joined by setting the eyelet 20.

Having reference to FIGURES 9 through 13, I will now more particularly describe the low voltage lampholder 12 used at the left end of the fluorescent lamp support arrangement shown in FIGURE 1. It will be seen that the low voltage lampholder 12 also utilizes a split housing arrangement and includes a front housing section 55, a rear housing section 56, a pair of contact strips 57, 58 and an eyelet 59. The rear housing section 56, as shown in FIGURE 11 is formed with a first projection 60 and a second projection 61 which extend outwardly for interlocking engagement with the front housing section 55. The first projection 60 including a pair of rib portions 62, 63 provides a guide wall for the conductor receiving aperture 64, 65, and the first projection 60 also locks the upper end of the contact strips 57, 58 in the cavities 66, 67 formed in the front housing section 55. The second projection 61 extends into front housing section 55 to lock the lower end of the contact strips 57, 58 in position. Both projections 60, 61 provide a stronger and more rigid unitary structure when housing sections 55, 56 are joined together because of the interlocking effect of the projections 60, 61. Also, the projections 60, 61 facilitate the assembly of the parts.

The contact strips 57, 58 used in this illustrated embodiment of the invention were essentially symmetrical. Accordingly, I have used the same reference numbers to identify the corresponding portions thereof, the portions of contact strip 58 being identified by primed numerals to distinguish them from the contact strip 57. As is best seen in FIGURE 13, the contact strip 57 includes a pin contact portion 70 and an angulated pressure lock portion 71· The pressure lock portion 71 includes an indentation 72 to facilitate entry of the conductor lead into pressure locking engagement. It will be noted that the contact strips 57, 58 are disposed in edgewise relation along the vertical wall 74 and the pin contact portions 70, 70' confront the lamp pin receiving aperture 75, so that when the lamp pin is inserted through the opening 75 the pin is resiliently engaged between the pin contact portions 70, 70'. Further, it will be noted that the rib 76 formed in the front housing section 55 provides the proper spacing for the pin contact portion 70, 70'.

It will be appreciated that although in the illustrated embodiments of the invention I have shown a pressure lock type of contact terminal for connection to the conductors, other types of terminal arrangements can be used.

The assembly of the low voltage lampholder involves combining five parts. The pressure lock portions 70, 70' of the contact strips 57, 58 are snapped into position in the cavities 66, 67 in the front housing section 55. The rear housing section 56 is then joined with the front hous10 ing section 55 by setting the eyelet 59 io complete th assembly.

From the foregoing description it will be apparent tha I have provided improved lampholder construction utiliz ing a split housing arrangement formed of two moldec housing sections of relatively shallow depth. An importan advantage of such an arrangement is that the mold time required to form these parts has been reduced as com parable lampholders of the prior art employing a singh molded part for the insulating housing. Further, the spli housing arrangement has made it possible to use simplifiec mold designs and thereby increase efficiency of the mold ing operation. Also, an improved spring-biased plungei arrangement has been provided. Further, the interlocking projections utilized in the improved split housing construction not only provide structural rigidity for the insulating housing when assembled on a fixture but alsc facilitate proper fitting and assembly of the parts durins manufacture.

While I have described herein exemplifications of the invention as applied to fluorescent lamps of the single pin type, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the invention. For example, the lampholders can be readily adapted to bi-pin type of fluorescent lamps and other terminal lead arrangements may be employed in conjunction with the improved arrangement. It is therefore intended in the following claims to cover all such equivalent variations as come within the true spirit and scope of this invention.