US3851295A

US3851295A - Self-locking lampholder

Info

Publication number: US3851295A
Application number: US00340026A
Authority: US
Inventors: B Geier
Original assignee: Bruce Industries Inc
Current assignee: Bruce Industries Inc
Priority date: 1973-03-12
Filing date: 1973-03-12
Publication date: 1974-11-26
Anticipated expiration: 1991-11-26

Abstract

A self-contained, self-locking fluorescent lampholder includes a one-piece housing which receives the functional and electrical components such as a slide lock assembly and locking fingers which operate to hold the pins of a fluorescent lamp in resilient engagement with the electrical contacts within the lampholder. The slide lock assembly is movable in the housing and easily operable and functions to protect against electrical shock when lamps are changed in an electrified lampholder, and to lock such lamps in place when positioned within the lampholder. The lampholder described finds special advantageous use in environments of vibration and narrow restricted areas, for example, in aircraft, rapid transit, pleasure craft and recreational vehicles.

Description

Geier Nov. 26, 1974 1 SELF-LOCKING LAMPHOLDER [21] Appl. No.: 340,026

[52] 11.5. CI. 339/54 51 Int. Cl H01! 13/54 [58] Field of Search 339/176 L, 75 R, 75 T, 339/45 T, 91, 273, 50-57 [56] References Cited UNITED STATES PATENTS 2,499,507 3/1950 Jordan 339/54 2,702,377 2/1955 Dahlhaus et a1. 339/54 X FOREIGN PATENTS OR APPLICATIONS 681,623 10/1952 Great Britain 339/54 880,178 6/1953 Germany 339/54 802,261 2/1951 Germany 339/54 1,211,716 3/1966 Germany 339/54 929.,147 12/1947 France 339/54 Primary Examiner-B0bby R. Gay Assistant Examiner-Terrell P. Lewis Attorney, Agent, or Firm-Geo. Fred Smyth 57 ABSTRACT A self-contained, self-locking fluorescent lampholder includes a one-piece housing which receives the functional and electrical components such as a slide lock assembly and locking fingers which operate to hold the pins of a fluorescent lamp in resilient engagement with the electrical contacts within the lampholder. The slide lock assembly is movable in the housing and easily operable and functions to protect against electrical shock when lamps are changed in an electrified lampholder, and to lock such lamps in place when positioned within the lampholder. The lampholder described finds special advantageous use in environments of vibration and narrow restricted areas, for example, in aircraft, rapid transit, pleasure craft and recreational vehicles.

10 Claims, 9 Drawing Figures l SELF-LOCKING LAMPI-IOLDER BACKGROUND OF THE INVENTION 1 This invention relates to a self-locking lampholder, and more particularly to an improved self-contained, self-locking lampholder for bipin fluorescent type lamps.

Heretofore the lampholders have utilized auxillary accessories to provide for the locking function. These items have resulted in the requirement of expending additional time for the installation of these extra pieces, on the lamp and/or light fixture, as well as the possibility of the loss of the extra pieces during relamping. Attemptshave been made to provide for the selflocking feature as an integral part of the lampholder. This has led to undesirable results, under shock and vibration environments particularly in the field of transportation.

The utilization of commercial materials has led to the generation of extremely fragile molded parts. This fragility has resulted in lampholder body breakage, which results in shorted terminals and ballast failures. In addition, the units utilize point contact connection between lamp terminals and lamp to ballast leads. This, due to vides an additional function during lamp removal procedures. This function is one of ejection. In an installation utilizing a narrow troffer for illuminated ceilings, the lamp may have limited clearance from the body of the fixture. This makes it difficult to grasp the lamp for removal, unless once released it is partially ejected from the lampholder. The lampholder of this invention provides for that type of operation. Moreover, the lampholder of this invention provides:

1. A self-contained, self-locking mechanism. Fluorescent tubes may be installed simply by inserting lamp terminals into slots on lampholder and depressing until the lock assembly automatically captures the pin terminals.

2. Release and partial ejection. When tube is to be removed, the lock assembly is depressed and lamp will release and partially eject for removal.

3. Shrouding and/or guarding of the exposed lamp terminals. The lamp is retained by the foot of the slide lock assembly after partial ejection, to prevent it from falling from fixture in ceiling mounting. Likewise the handle of slide lock also prevents the lamp terminals from coming into contact with a persons fingers while still energized thereby eliminating an electrical shock hazard.

4. Removal and insertion of the lamp in narrow and confining areas. A slide lock slot has been provided in proximity of the lamp terminals. The normal practice for replacement of fluorescent lamps is with electrical power on the light fixture, and thus the likelihood of an electrical shock hazard exists as the lamp is extracted from the electrified lampholder. In' addition, when the lamp is released it falls free from the retention of the lampholder and then may possibly fall from the fixture.

Reference is made to US. Pat. No. 2,502,944, of Apr. 4, I950, which describes a lampholder having a locking feature, but which is structurally different from the lampholder of this invention.

SUMMARY OF THE INVENTION The improved lampholder of this invention offers the advantage of being self-locking in the sense that the pin elements of a fluorescent tube are held by a locking mechanism which is entirely self-contained with no loose or extra parts. The basic elements of the lampholder of this invention are a housing, the electrical contact elements and a lock assembly which is slidable in the housing. By depressing a foot, the locking arms of the slide lock are moved to an unlocking position for removal of a bipin fluorescent tube.

Due to the relative simplicity of the lampholder of this invention, not only are the lamp terminals shrouded or guarded during assembly to and removal from the lampholder, but the lamp is retained to prevent it from falling free of the fixture, in the case of a ceiling mounting, for example.

By the present invention, a lampholder is provided which has several advantages. The construction of the electrical contacts not only provides for the continuous application of voltage to the lamp terminals, but prothe slide lock to allow the tube to be removed in narrow or restricted areas.

5. Electrical contacts provide for continuous electrical contact with the lamps during vibration and shock exposure. The fluorescent tube is not held rigidly when installed thus preventing damage to lamp filament from high vibration applications.

6. The fluorescent tube may be removed from either end when used in inaccessible areas.

7. The contacts are designed for applications of low filament voltages. The wiping action of contacts provides a low resistance connection between the lamp contact pins and the ballast circuit.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of a pair of lampholders of the present invention illustrating the mounting on the walls of an electric fixture in which a fluorescenttype lamp is supported;

FIG. 2 is a view of a single lampholder in accordance with this invention illustrating that portion into which the lamp pins are received;

FIG. 3 is a side elevational view taken along the line 3-3 of FIG. 2;

FIG. 5 is a view in perspective of the housing of the lampholder of the present invention, illustrating the interior of the housing without the movable and electrical components assembled thereto;

FIG. 6 is a view of the interior working parts of the lampholder of the present invention as seen by removing the rear cover assembly, and illustrating the locked position;

FIG. 7 is a view similar to that shown in FIG. 6, but illustrating the unlocked position of the lampholder of the present invention;

FIG. 8 is an enlarged side view of the spring used with the locking mechanism of the lampholder of the present invention; and

FIG. 4 is a top view taken along the line 44 of FIG.

FIG. 9 is an enlarged side view of the electrical contact elements used with the lampholder of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings which illustrate a preferred embodiment of the present invention, FIG. 1 diagrammatically shows the mounting of a conventional fluorescent discharge lamp 10 supported by a pair of spaced lampholders 1S and 16, mounted respectively on walls 17 and 19, which may for example be the opposite end walls of a lighting fixture. The lamps are of the conventional wellknown type adapted to be removably mounted in the lampholders which provide the electric power connection and physical support for the lamp. Both of the lampholders l5 and 16 are of essentially the same structure so that only one of the lampholders will be described in detail.

Referring to FIGS. 2-4, the lampholder includes a housing 20 containing the functional and electrical components to be described. Formed in the housing are pin receiving slots 22 into which the pins of the lamp are inserted. Mounted on the housing is a slide lock assembly 25 which is movable axially into and out of the housing. The external portion of the slide lock assembly 25 includes a foot member 26 proportioned to overlie the pin receiving slots 22 as illustrated in FIG..4. The external portion of the slide lock assembly 25 between the foot and outer portion of the housing is slotted, as indicated at 27, so that the pins on the end of the fluorescent tube may be moved laterally or sideways or rotated relative to the lampholder and then aligned with the pin receiving slots.

The housing is of a unitary construction and is enclosed by a cover, not shown, and the lampholder is intended to be mounted such that the cover is facing the mounting surface which is generally indicated at 28 in FIG. 3. The housing is provided with mounting holes 29, shown in FIG. 2, such that screwsor the like may be inserted through the housing, and through apertures in the back cover for mounting on the appropriate mounting surface. In this way, the cover is maintained secured to the housing by being clamped between the housing and the mounting surface. As illustrated, leadin wires 30 enter through the bottom wall 31 of the housing to provide the electrical connection between the power source and the lamp.

Referring to FIG. 5, there is shown the housing 20, with the cover removed and with the functional and movable parts removed in order to illustrate the interior configuration of the housing proper. Extending from the top of the housing to a position spaced from the bottom wall 31 is a slide lock guideway 35, generally of rectangular shape and located approximately in the center of the housing, as illustrated. As shown, the walls 36 of the slide lock guideway also constitute a common wall for the pin slots 22 which are adjacent to the slide lock guideway 35, the openings of the slots facing in the direction opposite to the guideway opening. On each side of the guideway, the housing includes a chamber 37 which receives the electrical contact elements for connection to the pins on the lamp. Verti cally above each of the contact chambers 37 is a vertical slot 38 communicating with the contact chamber and also communicating with the corresponding pin slot 22, the portion of the housing above the vertical slots forming a back wall 39 (FIG. 2) of the open or entry end of the pin slots 22.

The walls 36 of the slide lock guideway 35 are interrupted as indicated at 40 to provide a communicating passageway to the contact chamber 37. The lower end of the guideway 35 terminates in a wall 42 which is spaced from the bottom wall 31 of the housing 20, as indicated. The lower portion of the housing includes two spaced lead wire chambers 44, each disposed on one side of the slide lock guideway and separated from the associated contact chamber by a contact support shoulder 46. As illustrated, the bottom wall includes openings 47 through which the lead-in wires 30 pass, as will be described more fully hereinbelow.

The housing 20 also includes a peripheral shoulder 48 which extends from approximately the top of the slide lock guideway 35 to the bottom wall 31 and continues upwardly to the other spaced wall of the slide lock guideway. This shoulder receives a cover assembly which is secured in place by beveled snap pads 49, as shown in FIG. 5.

Referring now to FIG. 6, wherein like reference numerals have been used where applicable, the interior of the lampholder of the present invention is shown, the back cover having been removed so that the inside functional components may be seen. As seen in FIG. 6, the lampholder is in the locked position. The slide lock assembly 25 is bifurcated to form a pair of locking arms 51, each locking arm including a locking finger 52. The opposed face 53 of each locking finger 52 includes a slot 55 which receives a spring 60, the latter tending to urge the locking fingers 52 into the respective communicating contact chamber 37. As shown, each locking finger 52 is received in the passageway 40 of the slide lock guideway 35.

The facing

walls

62 and 63 of the passageway 40 are angled, as illustrated, and form cams which cooperate with the opposed cam surface which constitutues the facing surface of the respective locking fingers. As indicated, the spring is spaced from the bottom wall 42 of the slide lock guideway 35, the lower portion of the guideway constituting a spring chamber 66.

Received on each of the contact support shoulders 46 between the lead-in chamber and the contact chamber is a contact member 70, the contact shoulder being formed with a recessed shoulder 72 which receives the corresponding contact member to maintain the same properly aligned on the contact shoulder. With the back cover assembled, the back cover maintains the contact members 70 seated within their respective shoulders 72 on the contact support shoulder 46.

Attached to one end 76 of the contact member 70 is a lead wire 30, as illustrated, the lead wire passing through the aperture 47 furthest removed from the corresponding contact member. Thus, the lead-in wires 30 cross over in the chamber formed between the bottom wall 42 of the guideway and the bottom wall 31 of the housing. In this way, pulling forces on the lead-in wires do not apply tension to the solder connection between the lead-in wires and the one end 76 of the contact member 70, unless the pulling forces are substantial.

, The contact members 70 are of the same structure and include a U-shape end 76 (FIG. 9) and a flat section 78 which is received within the recessed contact shoulder 72. The contact member 70 also includes a flat leg 80 arranged at right angles to the flat section 78. the leg 80 being seated against a wall 81 of the contact support shoulder, the wall 81 facing into the contact chamber 37. The free end 83 of the contact member cooperates with the leg 80 to form a generally V- shaped resilient member. Thus, resilient contact is made between the contact member 70 through the free end 83, which forms a resilient leg, to a pin of the tube. Resilient contact is enhanced by having the leg 80 of the contact supported against the wall 81. In the locked position, the legs 52 of the slide lock assembly assist in maintaining the pins in contact with the free end 83 of the contact member, the relative positions of the free end 83 of the contact member 70 and the leg of the slide lock assembly being shown in FIG. 2.

Referring now to FIG. 7, the lampholder of the present invention is illustrated in the unlocked position. Here again, like reference numerals have been applied where applicable. As the slide lock assembly 25 is urged into the housing by pressing the slide lock foot 26, facing walls 63 cooperate with the opposed surface of the locking finger to cam the locking fingers towards each other as illustrated in FIG. 7. As long as pressure is applied to the foot 26, the fingers 52 will be in the relative positions illustrated in FIG. 7, the spring 60 tending to urge the fingers away from each other. As pressure is released, the spring 60 and the natural resiliency of the locking arms 51 tends to urge them away from each other, and the facing walls 62 cooperate with the opposed surfaces of the fingers 52 to assure that the locking fingers are returned to the locked position.

It will be seen with reference to FIG. 7, that in the unlocked position, the tip ends of the fingers are clear of the vertical slots 43 so that the pins of a fluorescent tube may be brought into tangential contact with the contact elements 70. In the unlocked position, it is also apparent that there is sufficient clearance to move the fluorescent tube and the pins thereon out of the pin slots 22, and the pins will then rest against the foot 26. Assuming that each end of the fluorescent tube is freed of the housing, the pins are in contact with the foot 26, as described, and the tube may be removed by rotating the pins around the foot 26, or moving the tube sideways such that the pins clear the slide lock slot 27.

Referring now to FIG. 8, the details of the spring 60 are shown, the latter including diverging legs 85 each of which is received within the locking finger slot 55 of the locking fingers 52. With the cover assembled to the housing, sideways movement (out of the plane of the drawing) of the locking spring 60 relative to the slots 55 is prevented.

The housing and cover are preferably of electrically insulating material such as plastic and the like. It has been found that electrical grade nylon with glass fiber filler, added for mechanical integrity, is a preferred material in accordance with this invention. The electrical contact elements are beryllium copper alloy, bright hardened to spring temper, and may be gold plated, if desired, while the spring may be of beryllium copper alloy and bright hardened to spring temper.

The lead-in wires may be affixed to the contacts in any conventional manner, and are preferably fully soldered and strain relieved for strength purposes.

As is apparent from the foregoing description, the electrical contacts are constructed so as to be in tangential contact with the circumferential periphery of the lamp pins, and are under tension so as to maintain electrical contact during exposure to vibration and shock environments. Also, it will be noted that the slide lock foot need not'be depressed when assembling a lamp. The locking arms may be depressed by applying pressure to the arms through the lamp pins so that the slide lock assembly is moved to the unlocked position by pressure on the locking arms rather than on the slide lock foot.

As illustrative of the relative size of the lampholder of the present invention, typical dimensions are as follows:

Housing length l.3l2 inches Overall length 1.67 inches (top of foot in locked position) Depth of housing .437 inches Width of housing 1.312 inches Lamps of varying size, from 15 to 48 inches may be used, and the lead-in wires may be of varying length depending upon the type of installation.

It will be apparent to those skilled in the art that various changes may be made to the apparatus shown and claimed herein, and it is recognized that this invention may be variously embodied and practiced within the scope of the following claims.

What is claimed as the invention is: l. A self-locking bipin lampholder comprising means defining a housing, said housing including contact receiving chambers and a slide lock receiving guideway,

pin receiving slots formed in said housing and so arranged as to communicate with said contact receiving chambers, slide lock means slidably received in said guideway and including a pair of spaced locking arms movable with respect to said slide lock means, each of said locking arms being received within said contact chamber, contact means received within said contact receiving chamber and including resilient leg means spaced from said locking arms,

said locking arms in the locked position urging the lamp pins into electrical contact with said contact means,

means urging said locking arms into locking position for engagement with lamp pins present in said contact chambers.

2. A self-locking lampholder as set forth in claim I wherein said slide lock is movable axially of guideway for effecting movement of said locking arms into and out of said contact receiving chamber.

3. A self-locking lampholder as set forth in claim I wherein said locking arms include a cam surface said guideway including cam means cooperating with the cam surface to urge said locking arms toward each other as said slide lock means is urged into said guideway in a direction toward said housing.

45. A self-locking lampholder as set forth in claim 1 wherein said spaced locking arms each include a locking finger,

said guideway including means defining slots oriented to be in communication with said contact chamber,

each said locking finger being slidable relative to the cooperating slot such that the corresponding locking finger is movable from a locking position in the corresponding contact chamber to an unlock position such that the end of the finger clears the pin slots sufficiently to permit insertion of lamp pins into said contact receiving chamber.

5. A self-locking lampholder as set forth in claim 4 wherein said guideway includes a chamber at one end thereof,

resilient means positioned in said chamber and cooperating with said locking fingers to urge the same into a locking position. 6. A self-locking lampholder as set forth in claim 1 wherein said guideway includes a bottom wall spaced from the end wall of said housing to define a lead-in chamber, said contact means including a pin contact portion and a lead wire contact portion, said lead wire contact portion being located in said lead-in chamber, lead wire means connected to each said contact means, means defining an opening in said housing for each lead wire, and said lead wires being so disposed that the wire passes through that opening furthest removed from the corresponding contact providing strain relief isolation between said lead wires and pin contact terminals. 7. A self-locking lampholder as set forth in claim 6 wherein said housing includes shoulder channel means between each of said contact chambers and said leadin chamber, each said contact means being received in the corresponding shoulder channel, and means to maintain said contact fixed in said respective shoulder channel. 8. A self-locking lampholder as set forth in claim 1 wherein each locking arm includes a locking finger movable into and out of the corresponding contact chamber,

each said locking arm includes a cam surface, said guideway including cam means cooperating with said camming surface to effect movement of said locking fingers into an unlocking position as said slide lock means is moved axially in said guideway, and

said locking fingers-operative in the unlocked position to permit passage of lamp pins in said pin receiving slots and in the locked position operative to urge the lamp pins against and in electrical contact with the corresponding resilient leg means of said contact means.

9. A self-locking lampholder as set forth in claim 1 wherein said locking arms are urged into a locking position preventing removal of the lamp pins axially out of pin receiving slots in the absence of movement of said slide lock means.

10. A self-locking lampholder for fluorescent type lamps comprising a housing having chamber means receiving electrical contact means for said lamp,

guideway means provided in said housing,

locking means mounted for movement in said guideway means,

pin receiving slots in said housing and communicating with said chamber means,

said locking means including locking fingers movable into said chamber means in locking position urging the pins of the lamp into engagement with said electrical contact means,

means urging said locking fingers into said locking position for preventing axial movement of the pins of the lamp in the pin slots, and

lead-in means cooperating with said electrical contact means.

Claims

1. A self-locking bipin lampholder comprising means defining a housing, said housing including contact receiving chambers and a slide lock receiving guideway, pin receiving slots formed in said housing and so arranged as to communicate with said contact receiving chambers, slide lock means slidably received in said guideway and including a pair of spaced locking arms movable with respect to said slide lock means, each of said locking arms being received within said contact chamber, contact means received within said contact receiving chamber and including resilient leg means spaced from said locking arms, said locking arms in the lockEd position urging the lamp pins into electrical contact with said contact means, means urging said locking arms into locking position for engagement with lamp pins present in said contact chambers.

2. A self-locking lampholder as set forth in claim 1 wherein said slide lock is movable axially of guideway for effecting movement of said locking arms into and out of said contact receiving chamber.

3. A self-locking lampholder as set forth in claim 1 wherein said locking arms include a cam surface said guideway including cam means cooperating with the cam surface to urge said locking arms toward each other as said slide lock means is urged into said guideway in a direction toward said housing.

4. A self-locking lampholder as set forth in claim 1 wherein said spaced locking arms each include a locking finger, said guideway including means defining slots oriented to be in communication with said contact chamber, each said locking finger being slidable relative to the cooperating slot such that the corresponding locking finger is movable from a locking position in the corresponding contact chamber to an unlock position such that the end of the finger clears the pin slots sufficiently to permit insertion of lamp pins into said contact receiving chamber.

5. A self-locking lampholder as set forth in claim 4 wherein said guideway includes a chamber at one end thereof, resilient means positioned in said chamber and cooperating with said locking fingers to urge the same into a locking position.

6. A self-locking lampholder as set forth in claim 1 wherein said guideway includes a bottom wall spaced from the end wall of said housing to define a lead-in chamber, said contact means including a pin contact portion and a lead wire contact portion, said lead wire contact portion being located in said lead-in chamber, lead wire means connected to each said contact means, means defining an opening in said housing for each lead wire, and said lead wires being so disposed that the wire passes through that opening furthest removed from the corresponding contact providing strain relief isolation between said lead wires and pin contact terminals.

7. A self-locking lampholder as set forth in claim 6 wherein said housing includes shoulder channel means between each of said contact chambers and said lead-in chamber, each said contact means being received in the corresponding shoulder channel, and means to maintain said contact fixed in said respective shoulder channel.

8. A self-locking lampholder as set forth in claim 1 wherein each locking arm includes a locking finger movable into and out of the corresponding contact chamber, each said locking arm includes a cam surface, said guideway including cam means cooperating with said camming surface to effect movement of said locking fingers into an unlocking position as said slide lock means is moved axially in said guideway, and said locking fingers operative in the unlocked position to permit passage of lamp pins in said pin receiving slots and in the locked position operative to urge the lamp pins against and in electrical contact with the corresponding resilient leg means of said contact means.

10. A self-locking lampholder for fluorescent type lamps comprising a housing having chamber means receiving electrical contact means for said lamp, guideway means provided in said housing, locking means mounted for movement in said guideway means, pin receiving slots in said housing and communicating with said chamber means, said locking means including locking fingers movable into said chamber means in locking position urging the pins of the lamp into engagement with said Electrical contact means, means urging said locking fingers into said locking position for preventing axial movement of the pins of the lamp in the pin slots, and lead-in means cooperating with said electrical contact means.