Abstract:
A fluorescent lamp holder assembly is adapted to receive various injection molded end cap structures allowing the fluorescent lamp holder assembly to have several embodiments, including watertight embodiments. The fluorescent lamp holder assembly may be disposable or may allow replacement of the fluorescent lamp, with the replacement style being watertight. The fluorescent lamp holder assembly generally includes a fluorescent lamp surrounded by a protective sleeve. A first end cap covers a first end of the lamp and sleeve, while a second end cap structure comprising a power connector cap and tube power connector cap covers a second end of the lamp and sleeve.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to lamp sockets, and, more particularly, to fluorescent lamp sockets. 
     2. Description of the Related Art 
     Fluorescent lamps, as known, include a glass tube coated on the inside with phosphor powders which fluoresce when excited by ultraviolet light. The glass tube is filled with rare gases (such as argon, neon, and krypton) and a small amount of mercury, and operates at a relatively low pressure. Electrodes are mounted within the glass tube and emit electrons during operation. The electrons are accelerated by the voltage across the tube until they collide with mercury atoms, causing the mercury atoms to be ionized and excited. When the mercury atoms return to their normal state, photons corresponding to mercury spectral lines in both the visible and ultraviolet region are generated, thereby exciting the phosphor coating on the inside of the tube to luminance. 
     To start a fluorescent lamp, electron emission from the electrodes may be induced in one of two ways. First, a filament electrode may be heated by passing current therethrough. Secondly, a high voltage which is sufficient to start an electric discharge in the lamp may be applied across the lamp without preheating the electrodes. Instant start circuits which are commonly used today typically employ the latter method of inducing electron emission from the electrodes. Instant start circuits use a ballast which applies a high voltage (e.g., up to 848 VAC) at a high frequency. Such instant start ballasts are much more energy efficient than older style ballasts which heat the electrodes. 
     Such fluorescent tubes come in a variety of styles and thus are used in a variety of applications. One such application is in commercial refrigeration illumination. Generally, a fluorescent lamp holder or assembly for such applications includes a fluorescent lamp surrounded by a protective plastic tube that are both retained on each end by a cap structure. One cap structure covers terminals on one end of the fluorescent lamp and the connection wires. The other cap structure couples the terminals of the other end of the fluorescent lamp to electrical power, generally by a power cord. Wires run the length of the protective plastic tube for appropriate connection to the terminals on the other end of the fluorescent lamp. Each cap structure is retained to the protective plastic tube by metal clips. The lamp assembly is generally retained within the refrigerator or freezer by clips. The power cord from the lamp assembly is wired into the power of the refrigerator. The above fluorescent lamp holder is, by its nature, disposable and not waterproof. Replacement of the fluorescent tube in the prior art holders is usually not recommended except by a skilled technician. Further, when the fluorescent lamp goes out, the entire holder must be unwired. 
     What is needed in the art is a fluorescent lamp holder which prevents electrical arcing between a conductor of the lamp holder and the contact pins of a fluorescent lamp. 
     What is also needed in the art is a fluorescent lamp holder that is waterproof for use in a moisture-laden environment. 
     Further needed in the art is a fluorescent lamp holder that allows replacement of the fluorescent lamp by any unskilled user. 
     SUMMARY OF THE INVENTION 
     The present invention provides a fluorescent lamp holder assembly adapted to accept various end cap structures. 
     In one form thereof, the fluorescent lamp holder is disposable. A protective sleeve surrounds the fluorescent lamp. A first end cap structure receives the fluorescent tube and protective sleeve and covers the wire connections to one set of terminals of the fluorescent tube. Preferably, the first end cap is permanently attached to the protective sleeve. A second end cap structure receives the other end of the protective sleeve and the fluorescent tube and includes a power attachment cap portion and a tube power connector cap portion. The power attachment cap portion receives one set of terminals of the fluorescent lamp and provides electrical coupling between the two sets of terminals of the fluorescent lamp with a source of electrical energy and is attached to the sleeve via an attachment clip. The tube power connector cap portion couples to the power attachment cap portion and provides a holder for the fluorescent tube and a pathway for the electrical wires for the second set of terminals. Preferably, the tube power connection cap portion is permanently attached to the protective sleeve. 
     In another form thereof, the fluorescent lamp holder provides replacement of the fluorescent tube. A first end cap structure includes terminal receptacles for receipt of one set of fluorescent lamp terminals. The receptacles are in communication with power wires of the holder and is preferably permanently attached to the protective sleeve. A second end cap structure includes a tube power attachment cap portion and a power attachment cap portion. The power attachment cap portion receives one set of terminals of the fluorescent lamp and provides electrical coupling between the two sets of terminals of the fluorescent lamp with a source of electrical energy. The tube power connector cap portion couples to the power attachment cap portion and provides a holder for the fluorescent tube and a pathway for the electrical wires for the second set of terminals. Preferably, the tube power connection cap portion is permanently attached to the protective sleeve. 
     It is an advantage of the present invention that various types of end cap structures may be used to provide various lamp assembly characteristics. 
     It is another advantage of the present invention that the lamp holder can be waterproof. 
     It is yet another advantage of the present invention that the lamp holder can be made disposable or replaceable. 
     It is another advantage of the present invention that various parts are injection molded, providing in one embodiment a watertight construction. 
     It is further an advantage of the present invention that one embodiment allows replacement of the fluorescent lamp to eliminate waste and the inconvenience of removing an old lamp holder and installing a new lamp holder. 
     It is still further an advantage of the present invention that it is usable with a variety of fluorescent tube styles with different pin configurations. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein: 
     FIG. 1 is a perspective view of a generic embodiment of the present fluorescent tube holder; 
     FIG. 1a is a perspective view of a typical fluorescent tube to be held by the present fluresenttube holder; 
     FIG. 2 is a partial side view of the outer tube of the present fluorescent tube holder; 
     FIG. 3 is a sectional view along line 3--3 of FIG. 2; 
     FIG. 4 is a side view of an attachment clip used in the present fluorescent tube holder; 
     FIG. 5 is a front view of the power coupling end cap of the present invention; 
     FIG. 6 is a cross-sectional side view of the power coupling end cap as taken along line 6--6 of FIG. 5; 
     FIG. 7 is a cross-sectional side view of one embodiment of an end cap as taken along line 7--7 of FIG. 8; 
     FIG. 8 is a front view of the end cap of FIG. 7 taken along line 8--8 thereof; 
     FIG. 9 is a front view of one embodiment of a tube power connector cap as taken along line 9--9 of FIG. 10; 
     FIG. 10 is a cross-sectional side view of the tube power connector cap of FIG. 9 taken along line 10--10 thereof; 
     FIG. 11 is a front view of another embodiment of a tube power connector cap as taken along line 11--11 of FIG. 12; 
     FIG. 12 is a cross-sectional side view of the tube power connector cap of FIG. 11 taken along line 12--12 thereof; 
     FIG. 13 is a front view of another embodiment of the end cap as taken along line 13--13 of FIG. 14; and 
     FIG. 14 is a cross-sectional side view of the end cap of FIG. 13 taken along line 14--14 thereof. 
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate preferred embodiments of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to FIG. 1 there is shown a fluorescent lamp holder/assembly generally designated 10. Fluorescent lamp holder 10 includes a fluorescent tube or lamp 12 that is radially surrounded by a protective sleeve, tube or cylinder 14 that is preferably made of a light-transmissive plastic. Fluorescent lamp 12 and sleeve 14 are received at one end thereof in end cap 16. The other end of fluorescent lamp 12 and sleeve 14 are received in tube power connector cap 18 which is coupled to power attachment cap 20. Sleeve 14 and power connector cap 18 are glued together and water-tight. Electrical power is provided to fluorescent lamp holder 10 via power cord 22 coupled to power attachment cap 20, wherein power cord 22 is wired to or in communication with a source 23 of electrical power (shown schematically in FIG. 1). Attachment clip 28, preferably of metal, is used to retain power attachment cap 20 to power connector cap 18. 
     As shown in FIG. 1a, fluorescent lamp 12 has two sets 13a and 13b of conventional electrical leads, terminals, prongs or the like, one set on either end thereof for attachment to appropriate electrical leads or wires supplying the necessary electrical power. 
     With reference to FIGS. 2 and 3, there is shown sleeve 14 in greater detail. Sleeve 14 is defined by an elongated tubular wall 24 having a longitudinally disposed thick portion 26 along the elongated length of sleeve 14. Bore or shaft 25 is disposed in thick portion 26 and thus extends the entire elongated length of sleeve 14. As shown in FIG. 3, bore or shaft 25 has an electrical leads 25a and 25b running therethrough to provide an electrical connection between end cap 16 and power connector cap 18. Tubular wall 24 defines an inner cavity or hollow 27 in which fluorescent lamp 12 is received. 
     FIG. 4 depicts attachment clip 28 which is defined by an arcuate or semi-circular portion 29 having radially inward flange 30 on one end thereof, and radially inward flange 31 on another end thereof, and may be used to secure the various caps to either style power connector cap 18. Flanges 30 and 31 are received in respective openings (see below) in the particular cap and engage power connector cap 18 for positive retention. 
     With reference to FIGS. 5 and 6, there is depicted power attachment cap 20 which is preferably injection-molded made from a suitable dielectric material such as plastic. Power attachment cap 20 is defined by a generally cylindrical body 34 having a radially outward notch 35 in a front portion thereof and end block 36. End block 36 defines inner surface 40 in which are disposed two power cable bores 37a and 37b as well as tube prong receptacles bores/tube power connection bores 38a and 38b. Power cable bores 37a and 37b and tube prong receptacles 38a and 38b are in communication with power cable 22 for supplying electrical power to fluorescent lamp 12. Power cable 22 includes power cable leads 22a and 22b, shown schematically. Power cable leads 22a and 22b are electrically coupled to power cable bores 37a and 37b, respectively, as well as tube prong receptacle bores 38a and 38b, respectively. Opening 42 is disposed in body 34 which along with a diametrically opposite opening (not shown) allow the use of attachment clip 28. 
     In accordance with the present invention, sleeve 14 and power attachment cap 20 are generic with respect to the various achievable embodiments of fluorescent lamp holder 10. 
     With reference now to FIGS. 7-10 there is depicted end cap 16a and tube power connector cap 18a which, along with sleeve 14 and lamp 12, provide a disposable embodiment of fluorescent lamp holder 10. In particular, FIGS. 7 and 8 depict end cap 16a. End cap 16a is defined by tubular shell 44 having end portion 45, preferably injection-molded made from a dielectric plastic, and is sized to receive an end portion of sleeve 14 and fluorescent lamp 12 within opening 46. Electrical leads leads 25a and 25b that extend through bore 25 of sleeve 14 are attached to the fluorescent lamp terminals that are covered by end cap 16a, such as with push-on type socket terminals which are slid over the male lamp terminals. Preferably, end cap 16a is permanently attached to sleeve 14 via glue, sonic welding, or the like. FIGS. 9 and 10 depict tube power connector cap 18a, preferably made from a dielectric plastic, which is defined by cylindrical shell 48 having end wall 49. Tube power connector cap 18a has internal cavity 60 sized and dimensioned to receive fluorescent lamp 12 and sleeve 14 therein. End wall 49 includes two fluorescent lamp prong/terminal bores 50 and 51 through which the prongs/terminals 13a and 13b of the appropriate fluorescent lamp extend. Adjacent end wall 49 is radial ledge 52 which defines a front surface 53 that provides a stop for the sleeve 14 when sleeve 14 is received therein. Ledge 52 is sized to allow the fluorescent lamp terminals/prongs 13a or 13b to sufficiently extend through bores 50 and 51 such that the fluorescent lamp terminals/prongs 13a or 13b are receivable into bores 38a and 38b of power attachment cap 20 when assembled. Tube power connector cap 18a further includes electrical terminal bores 54 and 55 that allow the electrical leads 25a and 25b emanating from power attachment cap 20 to extend therein and feed through shaft 25 of sleeve 14 to couple with the fluorescent lamp terminals/prongs 13a or 13b disposed within end cap 16a. Preferably, tube power connector cap 18a is permanently attached as by glue, sonic weld, or the like to sleeve 14 and when assembled, abuts power attachment cap 20. In this regard, tube power connector cap 18a has radially outward notch 58 that provides alignment and abuts inside notch 35 of power attachment cap 20. Additionally, O-ring 56 is provided for sealing as power attachment cap 20 extends over and around tube power connector cap 18a via opening 43. Two openings, of which one opening 59 is shown, provides attachment points for attachment clip 28 if used. 
     As tube power connector 18a joins with power connector cap 20, the fluorescent lamp terminals 13a or 13b that extend through bores 50 and 51 of end wall 49 of tube power connector 18a are received in bores 38a and 38b of power attachment cap 20. 
     Thus, by using end cap 16a and tube power connector cap 18a, along with sleeve 14 and power attachment cap 20, a disposable fluorescent lamp holder is produced. Of course, it should be understood that fluorescent lamp 12 would be inserted into sleeve 14 and the appropriate end caps before securing same. 
     With reference now to FIGS. 11-14, there is depicted end cap 16b and tube power connector cap 18b which, along with sleeve 14 and power attachment cap 20, provide a replaceable lamp embodiment of fluorescent lamp holder 10. In particular, FIGS. 13 and 14 depict end cap 16b. End cap 16b is defined by tubular shell 62 having end portion/block 64 and is sized to receive an end portion of sleeve 14 and fluorescent lamp 12 within opening 65. End cap 16b is overmolded using an injection molding process over terminals disposed within bores 66 and 67. Fluorescent lamp terminal/prong bores 66 and 67 are disposed in block 63 from front surface 64. Additionally, electrical lead bores 68 and 69 are disposed in block 63 from front surface 64 and are in communication with fluorescent lamp terminal/prong bores 66 and 67 by lateral bores 70 and 71 respectively. This allows the electrical leads 25a and 25b extending through bore 25 of sleeve 14 to be electrically connected to the fluorescent lamp terminals/prongs 13a or 13b that are received in fluorescent lamp terminal/prong bores 66 and 67. Preferably, end cap 16b is permanently attached to sleeve 14 via glue, sonic welding, or the like. For replacement, the old fluorescent lamp is easily removed from end cap 16b which carries the terminal receptacles 66 and 67, while a new fluorescent lamp is easily installed into bores 66 and 67 of end cap 16b by pressure. Sleeve 14 remains attached to end cap 16b. 
     FIGS. 11 and 12 depict tube power connector cap 18b, preferably injection-molded made from a dielectric plastic, which is defined by cylindrical shell 74. Tube power connector cap 18b has internal cavity 82 sized and dimensioned to receive fluorescent lamp 12 and sleeve 14. Adjacent an end thereof is radial ledge 77 which defines a front surface 78 that provides a stop for sleeve 14. Tube power connector cap 18b further includes electrical terminal bores 79 and 80 that allow the electrical leads emanating from power attachment cap 20 to extend therein and feed through shaft 25 of sleeve 14 to couple with the fluorescent lamp terminals/prongs 13a or 13b disposed within end cap 16b. Preferably, tube power connector cap 18b is permanently attached as by glue, sonic weld, or the like to sleeve 14 and when assembled, aligns to abut in power attachment cap 20. In this regard, tube power connector cap 18b has radially outward notch 76 that provides alignment and abuts in notch 35 of power attachment cap 20. Additionally, O-ring 75 is provided for sealing as power attachment cap 20 extends over and around tube power connector cap 18b via opening 43. Two openings, of which one opening 81 is shown, provides attachment points for attachment clip 28 if used. 
     For replacement of an old fluorescent lamp carried within the replaceable embodiment of the present lamp holder 10, power attachment cap 20 is removed from tube power connector cap 18b which disengages the terminals/prongs of the old fluorescent lamp from bores 38a and 38b. The old fluorescent lamp that thus extends from tube power connector cap 18b is pulled therefrom also disengaging the other terminals/prongs 13a or 13b from bores 66 and 67 of end cap 16b. A new fluorescent lamp is inserted through tube power connector cap 18b such that one set 13a or 13b of terminals/prongs engage bores 66 and 67 in end cap 16b. Thereafter, power attachment cap 20 is engaged over tube power connector cap 18b. 
     While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.