1. Technical Field
The disclosure generally relates to light emitting diode (LED) lamps, and particularly to an LED lamp with an adjustable lamp cap for facilitating assembly of the LED lamp to a lamp holder and facilitating adjustment of an illumination orientation of the LED lamp.
2. Description of Related Art
In recent years, LED lamps are preferred for use rather than CCFLs (cold cathode fluorescent lamps) and other light sources due to their excellent properties, including high brightness, energy saving, long lifespan, wide color range, and etc. Generally, a CCFL is elongated in profile and has a pair of electrically conductive poles provided at each of two ends of the CCFL. The conductive poles are inserted into a lamp holder, whereby the CCFL can get power through the lamp holder. Since the CCFL diffuses light outwardly from an outer surface thereof uniformly, the CCFL can be freely and easily mounted to the lamp holder without the need to adjust an illumination orientation of the CCFL. However, a light emitting surface of an LED is usually hemispherical and a beam angle of the LED is usually not larger than 120 degrees, which means the LED just can illuminate about two-thirds of a space in front of the LED emitting surface. Thus, an illumination orientation of the light emitting surface of the LED is very important to an LED lamp and should be accurately controlled. When the CCFL is substituted by the LED lamp and the LED lamp is mounted to the lamp holder which is originally used to mount the CCFL, an illumination orientation of the light emitting surface of the LED should be easily regulated to maintain the LED lamp to have a proper illumination orientation without bringing inconveniency for assembly the LED lamp to the lamp holder so that the LED lamp can be accurately and easily mounted to the lamp holder.
For the foregoing reasons, therefore, there is a need in the art for an LED lamp which overcomes the limitations described above.
Referring to
Referring to
The cooling member 11 is an elongated, hollow metal duct. A cross section of the cooling member 11 is substantially rectangular. An elongated rectangular chamber 113 is defined in the cooling member 11. The circuit board 60 is received in the chamber 113 of the cooling member 11, and is enclosed by a rectangular electrical insulator 70 which insulates the circuit board 60 from the cooling member 11. The circuit board 60 interconnects the LEDs 122 with the lamp caps 20, and provides drive power, control circuit and power management for the LEDs 122. Thus, after the lamp caps 20 of the LED lamp 100 are connected to a lamp holder, such as a traditional fluorescent lamp holder, electric current can be supplied to the LEDs 122 via the circuit board 60 to cause the LEDs 122 to generate light.
The cooling member 11 includes a heat absorbing plate 111 and a generally U-shaped heat dissipating plate 112 connecting with the heat absorbing plate 111. The heat absorbing plate 111 is an elongated sheet, and forms a flat heat absorbing surface 114 at a top side thereof. The substrate 121 of the light source 12 is arranged on the heat absorbing plate 111 and attached to the heat absorbing surface 114 closely, and heat generated by the LEDs 122 can be conducted to the cooling member 11 for dissipation via the substrate 121. The heat absorbing plate 111 defines two receiving grooves 115 respectively in left and right edges thereof for engaging with the lamp cover 13. A plurality of fixing holes 116 are defined in the heat absorbing plate 111 corresponding to the through holes 123 of the substrate 121.
A plurality of screws 102 respectively extend through the through holes 123 of the substrate 121 and threadedly engage into the fixing holes 116 of the heat absorbing plate 111, to thereby securely attach the substrate 121 to the heat absorbing surface 114 of the heat absorbing plate 111. An electrically insulating layer can be spread on each screw 102 to insulate the screw 102 from the circuits of the substrate 121. Further, a layer of thermal interface material (TIM) may be applied between the substrate 121 and the heat absorbing surface 114 of the heat absorbing plate 111 of the cooling member 11 to eliminate an air interstice therebetween, to thereby enhance a heat conduction efficiency between the LEDs 122 arranged on the substrate 121 and the heat absorbing plate 111 of the cooling member 11. Alternatively, the substrate 121 can be attached to the heat absorbing surface 114 fixedly and intimately through surface mount technology (SMT), whereby an interface between the substrate 121 and the heat absorbing plate 111 can be eliminated and a thermal resistance between the LEDs 122 and the heat absorbing plate 111 of the cooling member 11 is reduced.
The heat dissipating plate 112 includes two side walls 1121 and a connecting wall 1122. The two side walls 1121 extend vertically and downwardly from the left and right edges of the heat absorbing plate 111, respectively. The connecting wall 1122 interconnects bottom ends of the side walls 1121, and is parallel to the heat absorbing plate 111. In this embodiment, the heat absorbing plate 111 and the heat dissipating plate 112 of the cooling member 11 are integrally formed as a monolithic piece so as to reduce a thermal resistance therebetween. Alternatively, the heat dissipating plate 112 and the heat absorbing plate 111 of the cooling member 11 can be formed separately and then assembled together. The heat of the heat absorbing plate 111 absorbed from the LEDs 122 is finally dissipated to an ambient environment via the heat dissipating plate 112 which has a large heat exchanging area.
The lamp cover 13 is located above the LEDs 122, and assembled with the heat absorbing plate 111 of the cooling member 11. The lamp cover 13 functions as an optical lens for the LEDs 122, and guides light emitted by the LEDs 122 to the ambient environment. The lamp cover 13 is curved, and has a cross section being substantially C-shaped. A pair of protrusions 131 are respectively formed at left and right sides of the lamp cover 13 corresponding to the receiving grooves 115 of the heat absorbing plate 111. Each of the protrusions 131 extends inwardly from the lamp cover 13 into a corresponding receiving groove 115 of the heat absorbing plate 111 to assemble the lamp cover 13 onto the cooling member 11. Thus, the LEDs 122 are sealed between the lamp cover 13 and the cooling member 11, and are kept from environmental harm and mechanical damage.
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A lower ear 42 and an upper ear 43 protrude perpendicularly from the lower portion and the upper portion of the inner surface 411 of the sealing plate 41 towards the lamp tube 10, respectively. The upper ear 43 is arc-shaped, whilst the lower ear 42 is substantially rectangular and hollow. A slot 421 is defined in a bottom board 420 of the lower ear 42. A tab 423 extends from the bottom board 420 into the slot 421. A nub 422 is formed at a bottom of the tab 423; the nub 422 is lower than a bottom surface of the bottom board 420 of the lower ear 42. The tab 423 with the nub 422 can move upwardly into the hollow lower ear 42 under an upward force acting thereon. The connecting wall 1122 of the cooling member 11 defines two cutouts (not shown) respectively near two ends thereof, in which the cutouts are located respectively corresponding to the two nubs 422 of the two lower ears 42 of the two lamp caps 20.
A pin 45 extends perpendicularly outwardly from a middle of the outer surface 412 of the sealing plate 41 towards the connector 50. The pin 45 is cylindrical-shaped with a threaded hole 451 defined therein. A pair of positioning blocks 46 are formed on the outer surface 412 of the sealing plate 41, and located around the pin 45. The two positioning blocks 46 are the same with each other; each block 46 is arc-shaped. The positioning blocks 46 are located on an imaginary circle which is co-center with the pin 45. The two positioning blocks 46 are symmetrically disposed on two opposite sides of the pin 45, so that an angle formed between the two positioning blocks 46 relative to the pin 45 is a little smaller than 180 degrees.
Referring to
A seat 53 extends from a central portion of the base 51 into the cylinder 52. A mounting hole 531 extends through the seat 53 with a diameter substantially equaling to that of the threaded hole 451 of the pin 45. A sum of lengths of the seat 53 and the pin 45 is not larger than that of the cylinder 52. The conductive ring 56 is arranged around the seat 53, and insulates from the seat 53. Each of the pair of poles 55 extends through the base 51 with an inner end thereof in the cylinder 52 connected to the conductive ring 56 electrically and an outer end thereof located out of the cylinder 52 for connecting to the lamp holder. The wires which electrically connect the circuit board 60 with the connector 50 are connected to the conductive ring 56 of the connector 50 for electrically connecting the LEDs 122 to the poles 55 via the circuit board 60 and the conductive ring 56.
Particularly referring to
When the LED lamp 100 is assembled, the lamp caps 20 are arranged at opposite ends of the lamp tube 10, respectively. Then, the upper ear 43 and the lower ear 42 of each end cap 40 are pushed into the lamp cover 13 and the cooling member 11 of the lamp tube 10, respectively. Firstly, the lower ear 42 of each end cap 40 is pushed into the rectangular chamber 113 of the cooling member 11. The tab 423 of the lower ear 42 deforms when the nubs 422 encounter and engage into the cutouts of the connecting wall 1122. Then, the upper ear 43 of each end cap 40 slides into an inner surface of the lamp cover 13. Thus, the lamp caps 20 can not be taken apart from the lamp tube 10 for the engagement between the nubs 422 of the end caps 40 and the cutouts of the cooling member 11. Further, an outer periphery of the sealing plate 41 of each end cap 40 abuts the corresponding end of the lamp tube 10 to seal the corresponding end of the lamp tube 10.
When the present LED lamp 100 is mounted to the lamp holder, the poles 55 of the connectors 50 are inserted into the lamp holder, and thus the LEDs 122 of the LED lamp 100 can get power from an external power source via the lamp holder. In the present LED lamp 100, the connectors 50 and the end caps 40 are rotatably connected. During assembly of the LED lamp 100, the lamp tube 10 together with the end caps 40 can be easily rotated relative to the connectors 50 to obtain a proper illumination orientation for the LED lamp 100 in advance, and then the poles 55 of the connector 50 are manipulated to insert into the lamp holder. Alternatively, the poles 55 of the connector 50 can be manipulated to insert into the lamp holder in advance, and then the lamp tube 10 together with the end caps 40 are rotated relative to the connectors 50 to obtain a proper illumination orientation for the LED lamp 100. In the present LED lamp 100, the connectors 50 can be freely rotated in a range of less than 180 degrees relative to the lamp tube 10 to obtain a required illumination orientation for the lamp tube 10 without bringing inconveniency for assembly the LED lamp 100 to the lamp holder so that the LED lamp 100 can be accurately and easily mounted to the lamp holder. Particularly, when the lamp tube 10 is rotated to a position in which the positioning blocks 46 of the end caps 40 abut the latches 54 of the connectors 50, the LEDs 122 of the light source 12 are located at a horizontal level, and a light emitting surface of each LED 122 faces the ground directly under the LED lamp 100. The LED lamp 100 thus can be turned to a required illuminating orientation, and a utilization efficiency of the light of the LED lamp 100 is enhanced. In addition, since the connectors 50 of the present LED lamp 100 can be controlled to rotate relative to the lamp tube 10, assembly of the LED lamp 100 to the lamp holders is easy and convenient. Furthermore, since the connectors 50 are limited to rotate relative to the lamp tube 10 in a range of less than 180 degrees, the wires which electrically connect the circuit board 60 with the connector 50 are prevented from twisting off as a result of rotation more than 180 degrees.
Referring to
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The connector 50b has a seat 53b with an inner diameter substantially equaling to an outer diameter of the pin 45b. A pair of latches 54b extend outwardly from a free end of the seat 53b. Thus, when the connector 50b is assembled with the end cap 40b, the pin 45b is inserted into the seat 53b and the latches 54b are located between the blocks 46b. Therefore, the end cap 40b can be rotated relative to the connector 50b within an angle of 180 degrees.
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It is to be understood, however, that even though numerous characteristics and advantages of the disclosure have been set forth in the foregoing description, together with details of the structure and function of the disclosure, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
Number | Date | Country | Kind |
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200910303419.3 | Jun 2009 | CN | national |