1. Field of the Invention
The present invention relates to discharge lamps and fixtures therefor, and in particular, to lamps and fixtures that allow the lamps to illuminate across the entire fixture as well as pin connections to facilitate such entire illumination.
2. Description of Related Art
Discharge lamps operate by placing a relatively high potential between electrodes at opposite ends of a discharge tube filled with an inert gas that is stimulated by a discharge current through the tube. The discharge tube is typically coated internally with a phosphorescent material to convert ultraviolet light generated by the discharge into visible light. In conventional fluorescent lamps the electrodes may be filaments that are initially heated by an electrical current to thermally emit electrons and start the discharge current through the tube.
Since the discharge tubes are initially open at either end, lamp fabrication typically proceeds by inserting electrodes in the open ends. These electrodes may be mounted on leads embedded in a glass stem. This glass stem can be fused to the discharge tube. An evacuation tube integral with the glass stem can be used to evacuate the discharge tube before filling it with an inert gas and then sealing it.
Conventional fluorescent lamps have on each end of the discharge tube a pair of electrical pins that extend past the end of the tube parallel to the length of the tube. These pins are designed to fit into sockets located at either end of the discharge tube. When such a lamp and sockets are assembled, the lamp shines only along the active length of the discharge tube. Obviously, no light is emitted along the interval where the sockets are placed. The dark region is actually greater than the space occupied by the sockets since conventional fluorescent lamps are typically fitted at each end with a metal cap that blocks light.
If such assemblies are placed end to end there is a noticeable gap in the illumination in the vicinity of the sockets. These gaps cause uneven light distribution and can be visually objectionable when the lamps themselves are directly visible.
See also U.S. Pat. Nos. 2,029,628; 2,056,635; 2,160,786; 4,092,562; 4,278,911; 4,713,500; 4,863,394; 5,588,884; 5,906,427; 5,931,691; 5,969,938; 5,971,814; 6,139,347; 6,252,188; 6,749,470; 6,837,755; 7,063,555; 7,114,247; and D396,122; D424,230; and D521,173.
In accordance with the illustrative embodiments demonstrating features and advantages of the present invention, there is provided a discharge lamp including a discharge tube and a pair of electrodes mounted at opposite ends of the discharge tube. The discharge tube has a longitudinal centerline reaching between opposite ends of the tube. also included is a pair of connectors each connected to a different corresponding one of the pair of electrodes. Each of the connectors have at least one pin (a) externally mounted alongside the discharge tube without extending past the ends of the tube, and (b) extending at an angle no greater than an acute angle relative to the centerline.
In accordance with another aspect of the invention there is provided a fixture for a discharge lamp. The fixture includes an elongate housing and a pair of sockets mounted at opposite ends of the housing. Each of the sockets includes at least one longitudinal slot having an opening extending longitudinally between a proximal side of the slot and an open distal side of the slot. The longitudinal slot has an electrical contact.
In accordance with yet another aspect of the invention, there is provided a lighting assembly that includes a discharge tube and a pair of electrodes mounted at opposite ends of the discharge tube. The discharge tube has a longitudinal centerline reaching between opposite ends of the tube. Also included is a pair of connectors each connected to a different corresponding one of the pair of electrodes. Each of the connectors has at least one pin (a) externally mounted alongside the discharge tube without extending past the ends of the tube, and (b) extending at an angle no greater than an acute angle relative to the centerline. the assembly also has an elongate housing and a pair of sockets mounted at opposite ends of the housing. Each of the sockets includes at least one longitudinal slot having an opening extending longitudinally between a proximal side of the slot and an open distal side of the slot. The longitudinal slot has an electrical contact. The at least one pin of the pair of connectors is snapped into the longitudinal slot against the electrical contact of the pair of sockets.
By employing apparatus of the foregoing type, an improved discharge lamp and lamp fixture is achieved. In a disclosed embodiment, a discharge tube illuminates along its entire length including its end walls. Dark regions are avoided by mounting connectors on the side of the discharge lamp near its ends but without extending beyond the ends. In one embodiment cylindrical stubs extend radially from the side of a discharge tube and are sealed to glass stems that support an electrode that extends into the main cavity of the discharge tube. Consequently, this discharge lamp illuminates along its entire length and its connectors do not extend past the lamp bands to create a dark region.
In one embodiment, the lamp connectors include at each end a pair of inwardly directed electrical pins that are parallel to the centerline of the lamp. Using a pair of pins allows electrical heating of a filament inside the lamp's discharge tube, as is typical in a fluorescent lamp.
In this embodiment the lamp may be mounted in a fixture having mating sockets at either end. The socket can have a pair of slots with metal contacts for engaging the pins of the lamp connector. The slots may be adjacent to a receptacle for receiving a frame that cradles the lamp's discharge tube and supports the pair of electrical pins. The socket can also have male or female power connection devices for receiving incoming power and daisy chaining to other lamp fixtures.
The above brief description as well as other objects, features and advantages of the present invention will be more fully appreciated by reference to the following detailed description of illustrative embodiments in accordance with the present invention when taken in conjunction with the accompanying drawings, wherein:
Referring to
Tube 14 has a pair of transverse tubular stubs 18 located inwardly from each of the two walls 16. Stubs 18 are first installed as open cylindrical glass sleeves fused to a mating opening in the circumference of tube 14. The distal ends of stubs 18 are then fused to glass stem 20. Stem 20 is fabricated with a pair of electrical leads 24 embedded therein. Electrical leads 24 each emerge from opposite ends of stem 20. The inside ends of leads 24 are bent and crimped onto opposite ends of electrode 26, shown herein as a spiral filament. Electrode 26 may be spaced inwardly from wall 16 (
Before installation, stem 20 may have an integral evacuation tube (not shown) communicating with tunnel 22 originally running the length of stem 20. When stem 20 is first installed on stub 18 the evacuation tube will communicate through tunnel 22 to the interior of discharge tube 14. In a conventional manner, the evacuation tube can be used to evacuate discharge tube 14 and refill it with an inert gas. The evacuation tube is then sealed (tipped-off) to seal tube 14, and doing so will partially collapse tunnel 22. Discharge tube 14 is in this embodiment ½ inch (1.3 cm) in diameter (T8 size) although other sizes are contemplated (T2, T5, T12, etc.). In this embodiment tube 14 is 19 inches (48 cm) long although other lengths are contemplated and the axis of the tube 14 need not be straight in all embodiments. In fact, tube 14 will not be cylindrical in some embodiments. Also, stub 18 is about ⅜ inch (1 cm) in diameter, although again, this dimension will vary depending upon lamp size and other physical considerations.
Transverse stub 18, when finished, fits inside cradle 28, shown as a five sided box with a proximal face 28A, distal face 28B, two sidewalls 28, and a floor 28D. Sidewalls 28C are capped with a bead 30 and have a detaining nub 29 in the shape of a triangular prism (for purposes to be described presently). Walls 28A and 28B have a arced border designed to engage and cradle the circumference of discharge tube 14. Cradle 28 is plastic and about ½ inch (1.3 cm) long although different sized cradles may be used depending upon the lamp size and other physical considerations.
A cantilevered pair of tubular pins 32 are mounted in openings in proximal wall 28A with flanges 32A abutting wall 28A. In particular, the tubular inside end of pins 32 are swaged in place. The external ends of leads 24 are separately threaded through tubular pins 32 before crimping pin 32 as indicated by crimping dimples 34. Any excess length of lead 24 protruding past the end of pin 32 can be snipped off. In this embodiment exposed length of pins 32 are approximately ½ inch (1.3 cm) and spaced about ½ inch (1.3 cm) apart, although different lengths and spacings may be employed in other embodiments.
Pins 32 on each of the connectors 12 point inwardly toward each other end, extend in the same direction as centerline 14A, and are in fact parallel (although being parallel is not necessary because some non-parallel pins will still be deemed to point toward each other or extend in the same direction as a centerline, which centerline need not be straight). The interior of cradle 28 is filled with a potting compound that holds together and reinforces this assembly.
Referring to
Central ridge 46 has an opposing pair of shelves 46A partially forming a floor for slots 40. The insides of ridges 44 each have an inwardly directed shelf 44A located slightly below shelves 46A as well as an inwardly directed shelf 44B located below shelf 44A. A pair of internal pins 54 project perpendicularly from wall 36B just over shelves 44B.
A pair of lamp contacts 52 are shown as metal strips each with a right angle bend that fits between shelf 44B and pin 54. Electrical leads 53A and 53B (shown in phantom) are soldered to contacts 52 near these bends. Each of the electrical contacts 52 extend from shelf 44B, between shelves 44A and 46A, and into slots 40. An edge of the contacts 52 fit into the corners formed between wall 36B and the parallel ridges 56 formed on the inside of wall 36B. The ends of contacts 52 in slots 40 have a zigzag bend for presenting a convex/concave surface to the slot. The inside faces of ridges 44 are relieved to provide clearance allowing the contacts 52 to flex away from each other.
The insides of walls 58A each have a parallel pair of guide ridges 63 and 64 (walls 58A are mirror images of each other). Contact holder 36 can slide between guide ridges 63 and 64. The insides of walls 58A also have an opposite pair of rectangular recesses (not shown) for slidably receiving power connection device 66.
Power connection device 66 of
Elements 36 and 66 are captured by cover plate 72 and therefore cannot slide downwardly out of frame 58. Plate 72 is held in place by screw 73, which is threaded into a stud (not shown) depending from a wall (also not shown) bridging walls 58A. Elements 36 and 66 cannot slide upwardly out of frame 58 because their respective shoulders 36C and 66A engage overhanging stops (not shown) on the inside of walls 58A.
A grounding clip 74 is shown as a metal strip having one end folded to form a hook that slips over the edge of cover plate 72 between ridges 76. The longer leg of clip 74 is bowed and lies along the outside of cover plate 72 in order to make electrical contact with a housing to be described presently. Grounding clip 74 is electrically connected to tubular ends 67A of the ground contacts of block 66 as indicated by previously mentioned phantom lead 71, which may be soldered to clip 74.
When slid into place, contact holder 36 extends from cover plate 72 between ridges 63 and 64 to just past the opposite edge of walls 58A. As a result, distal face 36B of holder 36 bounds one side of a receptacle 76 that is also bounded on two other sides by walls 58A. The fourth side of receptacle 76 is bounded by the edge of annular wall 58B. Receptacle 76 is designed to receive the previously mentioned cradle (cradle 28 of
Referring to
In
This configuration constitutes a female power connection device located at one end of housing 82. The opposite end of housing 82 is fitted with a male power connection device whose trio of pins 88 and 89 are visible in
Power is supplied to the unit of
Referring to
The power received on terminals 90 is applied to electrical circuit 96 mounted on circuit board 92. In this embodiment circuit 96 is a conventional instant start, no flickering, silent electronic ballast. Circuit 96 initially provides on output terminals 91 a current for incandescently heating the lamp filament (filament 26 of
Once the incandescently heated filaments begin thermally emitting electrons, circuit 96 will then apply a discharge voltage between the two filaments to support a discharge current through tube 14 in the usual manner. This discharge voltage may be conventional house current at 120 V, 60 Hz (or other voltages depending upon local standards; or a much higher voltage in the case of neon lights, cold cathode lamps, etc.).
Referring to
To facilitate an understanding of the principles associated with the foregoing apparatus, its operation will be briefly described. When installing or replacing the lamp, lamp 10 of
Accordingly, contacts 52 (
In a known manner, the discharge current from filament electrodes 26 (
Consequently, this lighting assembly will provide illumination along its entire length. In instances where the units are connected and abutted end to end, the illumination will extend from unit to unit effectively without a dark gap.
It is appreciated that various modifications may be implemented with respect to the above described embodiments. While parts of the previously mentioned connector and socket are described as injection molded plastic, other embodiments may use ceramic, phenolic or other insulating materials. Also, while the previously mentioned cradle and receptacle are rectangular, in other embodiments these components may be cylindrical, a triangular prism, or have other shapes. In addition, these components may be made from a number of pieces that attach together by snap fittings, glue, pin and socket joints, or other means. The previously illustrated electrical pins may in some embodiments be curved, tapered, flared, have enlarged ends, or have other shapes. Also, these pins may be parallel to the length of the discharge tube or skewed at an angle that is less than acute, that is, less than 90° (for example, 45°). While a parallel pair of inwardly pointing pins are shown, some embodiments may have a pair of pins on one end of the lamp that point in opposite directions (either lengthwise or transverse to the length of the discharge tube). Moreover, some embodiments may have pins that are located in cavities on cradles mounted the side of the discharge tube. Also, some lamps (e.g., neon lamps, cold cathode lamps, etc.) may only have a single pin on each end of the lamp. Moreover, the lamp socket may have contacts in the form of a pair of metal fingers that squeeze each pin from opposite sides. In addition, some embodiments may have lamp sockets with contacts that slide axially onto the electrical pins of the lamp. While the illustrated lamp fixture is shown as a single unit, in some embodiments separate sockets can be provided that are mounted onto a wall or other structure at a distance and with an alignment appropriate to receive and connect to the lamp.
Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.